🔴 Measles (Rubeola) - First Disease

📋Disease Overview

Key Characteristics

Causative Agent: Measles virus (Paramyxovirus family, RNA virus)

Transmission: Highly contagious - airborne droplets, 90% attack rate in susceptible contacts

Incubation Period: 10-14 days (range: 7-21 days)

Contagious Period: 4 days before to 4 days after rash onset

Peak Age: Unvaccinated children 1-5 years (can occur at any age)

Seasonality: Winter-Spring in temperate climates

Public Health Emergency: Measles is a notifiable disease. Report immediately to local health department. Highly contagious (R0 = 12-18). Can cause outbreaks in under-vaccinated populations.

Classic Clinical Triad

1. The 3 C's: Cough, Coryza (runny nose), Conjunctivitis

2. Koplik Spots: Pathognomonic - small white spots on buccal mucosa (opposite molars)

3. Maculopapular Rash: Starts at hairline/behind ears → spreads cephalocaudally

🩺Clinical Presentation

Three-Stage Disease Course

Stage 1: Prodromal (Days 1-4)

Features:

High fever: 39-40.5°C (103-105°F)
The 3 C's: Cough (hacking), Coryza (profuse nasal discharge), Conjunctivitis (red, watery eyes with photophobia)
Malaise, irritability, anorexia
Koplik spots: Appear 2-3 days before rash (pathognomonic but transient)

Most contagious phase!

Stage 2: Exanthem (Days 3-7)

Rash Characteristics:

Onset: Day 3-4 of illness (after Koplik spots)
Location: Starts at hairline, behind ears, forehead
Spread: Cephalocaudal (head to feet) over 3-4 days
Appearance: Erythematous maculopapular, begins as discrete lesions → becomes confluent on face/upper trunk
Color: Red to reddish-brown
Duration: 5-7 days

Fever peaks (40-40.5°C) with rash onset, then gradually resolves

Stage 3: Recovery (Days 7-14)

Features:

Rash fades in order of appearance (face first)
Desquamation (fine, branny scaling) - NOT like scarlet fever
Cough may persist for 1-2 weeks
Temporary immunosuppression (3-4 weeks)

📸 Clinical Images Reference:
Koplik spots: White papules with red halo on buccal mucosa
Rash: Confluent maculopapular eruption starting at hairline
Distribution: Face → trunk → extremities progression

Modified Measles (Vaccinated/Partially Immune)

Presentation: Milder disease, shorter duration, less severe symptoms

Rash: May be sparse or atypical

Fever: Lower grade

Contagious: Still contagious but less so

🔬Diagnosis

Clinical Diagnosis Criteria (WHO)

Fever ≥38°C (100.4°F)
PLUS

Maculopapular rash
PLUS at least ONE of:

Cough
Coryza
Conjunctivitis

Laboratory Confirmation Required: Clinical diagnosis should be confirmed with laboratory testing, especially in outbreak settings or for public health reporting.

Laboratory Confirmation Grade A

Test	Specimen	Timing	Notes
Measles IgM antibody	Serum	Day 3-28 after rash onset (optimal: 3-7 days)	Most common confirmatory test. May be false negative if collected too early (<3 days)
Measles IgG seroconversion	Serum (paired)	Acute & convalescent (2-4 weeks apart)	4-fold rise in IgG titer confirms acute infection
RT-PCR	Nasopharyngeal swab, throat swab, urine	Within 7 days of rash onset	Rapid, specific. Allows genotyping for outbreak investigation
Viral culture	Nasopharyngeal swab, urine	Within 3-7 days of rash onset	Time-consuming, for genotyping. Less commonly used

Recommended Laboratory Workup

For diagnosis: Measles IgM + RT-PCR (if available)
Baseline: CBC (lymphopenia common), CMP
If complications suspected: CXR, LFTs, amylase/lipase
Vitamin A level: If deficient (risk factor for severe disease)

Differential Diagnosis

Disease	Key Distinguishing Features
Rubella	Milder symptoms, posterior cervical/occipital lymphadenopathy, no Koplik spots
Roseola	Rash appears AFTER fever resolves, younger age (6-24 months)
Scarlet fever	Sandpaper texture, strawberry tongue, circumoral pallor, positive Strep test
Drug reaction	History of new medication, no prodrome, no Koplik spots
Kawasaki disease	≥5 days fever, conjunctivitis (non-purulent), extremity changes, lymphadenopathy

💊Treatment & Management

No Specific Antiviral Treatment: Management is primarily supportive. Focus on preventing complications and secondary infections. Isolate patient until 4 days after rash onset.

🏠 Supportive Care Grade A

Fever management: Acetaminophen 10-15 mg/kg/dose q4-6h OR Ibuprofen 5-10 mg/kg/dose q6-8h
Hydration: Encourage oral fluids, IV fluids if severe dehydration
Rest: Bed rest during acute illness
Nutrition: Soft diet as tolerated, nutritional support
Eye care: Dim lighting if photophobia, clean discharge gently
Skin care: Keep skin clean, avoid scratching
Humidified air: For cough and respiratory symptoms

💉 Vitamin A Supplementation Grade A

WHO Recommendation: ALL children with measles should receive vitamin A. Reduces severity, complications, and mortality by 50%.

Age-Based Dosing (WHO/AAP):

Infants <6 months: 50,000 IU PO once daily × 2 days
6-11 months: 100,000 IU PO once daily × 2 days
≥12 months: 200,000 IU PO once daily × 2 days

Children with vitamin A deficiency signs: Third dose at 2-4 weeks

Indications for Vitamin A (AAP):

All children hospitalized with measles
Age 6 months-2 years not hospitalized but with risk factors:

Immunodeficiency
Evidence of vitamin A deficiency (night blindness, xerophthalmia)
Recent immigrant from high-mortality area
Malabsorption (cystic fibrosis, IBD)
Moderate to severe malnutrition

🏥 Hospitalization Criteria

Age <1 year
Immunocompromised patients
Pneumonia or respiratory distress
Dehydration requiring IV fluids
Encephalitis or altered mental status
Severe complications (see below)
Inability to tolerate oral intake
Social factors preventing adequate home care

🦠 Complications (Occur in ~30% of cases)

Common Complications

Complication	Frequency	Management
Otitis media	7-9%	Antibiotics if bacterial superinfection
Pneumonia	1-6%	Supportive care, antibiotics for secondary bacterial infection. Leading cause of death
Diarrhea	8%	Hydration, nutritional support
Laryngotracheobronchitis (Croup)	Variable	Nebulized epinephrine, corticosteroids

Severe/Life-Threatening Complications

Encephalitis (Acute Measles Encephalitis):
• Frequency: 1 per 1,000 cases
• Onset: Within 2 weeks of rash
• Features: Fever, seizures, altered mental status, coma
• Mortality: 10-15%, permanent neurologic sequelae in 25%
• Management: Supportive ICU care, seizure control

Subacute Sclerosing Panencephalitis (SSPE):
• Frequency: 7-11 per 100,000 cases (higher if infected <2 years)
• Onset: 7-10 years after acute measles
• Features: Progressive neurodegeneration, behavioral changes, myoclonus, dementia, death
• Prognosis: Universally fatal within 1-3 years
• Prevention: VACCINATION!

Other Severe Complications	Details
Thrombocytopenia	1 per 3,000 cases; usually self-limited
Hepatitis	Transient elevation of transaminases common
Myocarditis	Rare but can be fatal
Appendicitis	Measles can involve lymphoid tissue of appendix
Death	1-3 per 1,000 cases in developed countries; higher in malnourished/immunocompromised

🛡️ Post-Exposure Prophylaxis Grade A

Definition of Exposure: Being in the same room or enclosed area as someone with measles, or direct contact with infectious respiratory secretions. Time frame: From 4 days before to 4 days after rash onset.

Option 1: MMR Vaccine (Preferred for eligible)

Indications:
• Susceptible individuals ≥6 months old
• Non-immune or inadequately immunized contacts

Timing: Within 72 hours of exposure

Efficacy: Up to 95% effective if given within 72 hours

Note: If given at 6-11 months, does NOT count toward routine immunization schedule (still need 2 doses at ≥12 months)

Option 2: Immunoglobulin (IG)

Indications:
• Infants <6 months
• Pregnant women without evidence of immunity
• Severely immunocompromised patients (cannot receive MMR)

Dose:
• Immunocompetent: 0.5 mL/kg IM (max 15 mL)
• Immunocompromised: 0.5 mL/kg IM (max 15 mL), some recommend up to 0.5 mL/kg

Timing: Within 6 days of exposure (preferably within 72 hours)

Note: May attenuate but not prevent disease. Delays MMR for 6 months.

No Prophylaxis Needed:

Documentation of 2 doses MMR (≥28 days apart, first dose ≥12 months)
Laboratory evidence of immunity (positive IgG)
Laboratory confirmed measles in the past
Born before 1957 (likely immune, but confirm if working in healthcare)

🏥 Isolation Precautions

Airborne Precautions Required!
• Single room with negative pressure ventilation
• N95 respirator for all entering room
• Duration: Until 4 days after rash onset
• Healthcare workers: Must have documented immunity
• Virus can remain airborne for up to 2 hours after infected person leaves

References: CDC. Measles (Rubeola). Pink Book. 2021. | AAP. Red Book: 2021-2024 Report of the Committee on Infectious Diseases. 32nd ed. | WHO. Measles vaccines: WHO position paper. Wkly Epidemiol Rec. 2017;92(17):205-228.

🌸 Rubella (German Measles) - Third Disease

📋Disease Overview

Key Characteristics

Causative Agent: Rubella virus (Togavirus family, RNA virus)

Transmission: Respiratory droplets, less contagious than measles

Incubation Period: 14-21 days (average 16-18 days)

Contagious Period: 7 days before to 7 days after rash onset

Peak Age: 5-9 years (vaccine-preventable)

Critical Concern - Congenital Rubella Syndrome (CRS): Rubella infection during pregnancy (especially first trimester) can cause devastating fetal malformations. Up to 90% risk in first 12 weeks. This is the primary reason for rubella vaccination programs.

Clinical Features

Classic Triad

1. Low-grade fever: Usually <38.5°C (101°F)

2. Maculopapular rash: Pink, discrete, starts on face → spreads to trunk/extremities

3. Lymphadenopathy: Posterior cervical, postauricular, occipital (CHARACTERISTIC!)

Prodrome (1-5 days before rash)

Mild constitutional symptoms
Low-grade fever
Headache
Malaise
Mild conjunctivitis (less severe than measles)
Coryza (mild)

Rash Characteristics

Appearance: Pink-red maculopapular, discrete (doesn't usually become confluent)

Distribution: Face (forehead) → trunk → extremities within 24 hours

Duration: 3 days typically ("3-day measles")

Fading: Clears in same order it appeared, no desquamation

Forchheimer spots: Petechiae on soft palate (20% of cases, not specific)

⚠️ Complications (Rare in Children)

Complication	Frequency	Notes
Arthralgia/Arthritis	Common in adult women (70%), rare in children	Fingers, wrists, knees. Self-limited, lasts 1-2 weeks
Thrombocytopenia	1 in 3,000	Usually self-limited
Encephalitis	1 in 6,000	20% mortality, 30% permanent sequelae
SSPE	Very rare	Progressive rubella panencephalitis (immunocompromised)

Congenital Rubella Syndrome (CRS):

Risk by trimester:
• <12 weeks: Up to 85-90% risk of CRS
• 13-16 weeks: 10-20% risk
• >20 weeks: Rare

Classic CRS Triad:
1. Cardiac defects (PDA, pulmonary stenosis, VSD)
2. Cataracts, glaucoma, retinopathy
3. Sensorineural deafness (most common, may be isolated)

Other manifestations: Microcephaly, intellectual disability, growth restriction, hepatosplenomegaly, thrombocytopenia ("blueberry muffin" purpura), meningoencephalitis, bone lesions

Prevention: Ensure all women of childbearing age are immune (2 doses MMR or positive IgG) BEFORE pregnancy

🔬Diagnosis

Laboratory confirmation required: Clinical diagnosis unreliable (30-50% of cases are subclinical or mild). Must confirm for public health reporting and pregnancy exposure management.

Laboratory Tests

Test	Specimen	Interpretation
Rubella IgM	Serum	Positive: Acute infection (appears 4-5 days after rash, peaks 7-10 days, persists 4-8 weeks). Can have false positives
Rubella IgG seroconversion	Serum (paired)	4-fold rise between acute and convalescent (2-3 weeks apart) confirms infection
RT-PCR	Nasopharyngeal swab, throat swab, urine	Detects viral RNA. Most sensitive in first week after rash. Allows genotyping
Viral culture	Nasopharyngeal swab, urine	Less commonly used, takes longer. For genotyping

Differential Diagnosis

Measles: More severe, Koplik spots, cough/coryza/conjunctivitis prominent
Scarlet fever: Sandpaper rash, strawberry tongue, no lymphadenopathy pattern
Roseola: Younger age, rash after fever resolves
Erythema infectiosum: "Slapped cheek," lacy reticular rash on extremities
Enteroviral infection: Variable presentation, often summer/fall
Drug reaction: Medication history, no prodrome

💊Management

Treatment (Supportive Only)

No specific antiviral therapy
Antipyretics: Acetaminophen or ibuprofen for fever/discomfort
Rest: Activity as tolerated
Hydration: Maintain adequate fluid intake
Isolation: Until 7 days after rash onset

🤰 Pregnancy Exposure Management

URGENT evaluation required for ANY pregnant woman exposed to rubella!

Step 1: Determine Immune Status

Check documented immunity: 2 doses MMR OR positive rubella IgG
If status unknown: Draw rubella IgG immediately

Step 2: If Non-Immune or Unknown

Testing protocol:
• Draw rubella IgG and IgM immediately (baseline)
• Repeat IgG and IgM at 3-4 weeks post-exposure
• If either IgM positive OR IgG seroconverts → Acute infection confirmed

Step 3: If Infection Confirmed

Counsel about CRS risks (85-90% if <12 weeks gestation)
Detailed fetal ultrasound
Amniocentesis for viral PCR (after 12 weeks gestation if desired)
Pediatric infectious disease and maternal-fetal medicine consultation
Discuss options with patient (continuation vs termination based on gestational age and local laws)

Immunoglobulin NOT effective for post-exposure prophylaxis in pregnancy. Should NOT be used.

Prevention

Screen ALL women for rubella immunity before or early in pregnancy
Vaccinate non-immune women postpartum (MMR is live vaccine, cannot give during pregnancy)
Advise to avoid pregnancy for 28 days after MMR vaccination

🛡️ Prevention - MMR Vaccine Grade A

Routine Schedule:
Dose 1: 12-15 months
Dose 2: 4-6 years

Efficacy: 97% after 2 doses
Duration: Lifelong immunity in most

Contraindications:
• Pregnancy
• Severe immunodeficiency
• Recent immunoglobulin administration
• History of severe allergic reaction to vaccine component

References: CDC. Rubella. Pink Book. 2021. | AAP. Red Book. 2021-2024. | McLean HQ, et al. Prevention of measles, rubella, congenital rubella syndrome, and mumps: Summary of CDC recommendations. MMWR Recomm Rep. 2013;62(RR-04):1-34.

👋 Erythema Infectiosum (Fifth Disease)

📋Disease Overview

Key Characteristics

Causative Agent: Parvovirus B19 (single-stranded DNA virus)

Transmission: Respiratory droplets, vertical transmission, blood products

Incubation Period: 4-14 days (up to 21 days)

Contagious Period: BEFORE rash appears (during prodrome). Not contagious once rash develops!

Peak Age: 5-15 years (school-age children)

Seasonality: Winter-Spring, occurs in outbreaks

Key Point: Children with typical rash are NOT contagious and do NOT need to be excluded from school or daycare. Contagiousness occurs before rash (during viral prodrome).

Classic Clinical Presentation

Phase 1: Prodrome (Days 1-7, often absent or mild)

Low-grade fever (15-30% of patients)
Mild upper respiratory symptoms
Headache, malaise
MOST CONTAGIOUS PHASE (before anyone knows child is sick!)

Phase 2: "Slapped Cheek" Rash (Days 7-10)

Bright red, confluent erythema on cheeks (PATHOGNOMONIC!)
Circumoral pallor (sparing around mouth and nose)
May have mild edema of face
Child usually feels well at this point
NOT contagious once rash appears

Phase 3: Reticular Rash (Days 10-14, can last weeks)

Lacy, reticular (net-like) rash on trunk and extremities
Appears 1-4 days after facial rash
Spares palms and soles typically
Can wax and wane for weeks to months
Exacerbated by: Heat, sunlight, exercise, emotional stress, bathing
May be pruritic

📸 Clinical Images Reference:
"Slapped cheek" appearance: Bright red, confluent erythema on both cheeks with circumoral pallor
Reticular rash: Lacy, net-like pattern on arms, legs, trunk

⚠️ Complications & High-Risk Groups

1. Aplastic Crisis (Patients with Hemolytic Anemias)

High Risk: Sickle cell disease, hereditary spherocytosis, thalassemia, G6PD deficiency

Mechanism: Parvovirus B19 infects RBC precursors → temporary cessation of RBC production

Presentation:
• Severe anemia (Hgb may drop 5-6 g/dL)
• Pallor, weakness, fatigue
• No rash typically
• Reticulocytopenia (KEY finding)
• May have fever, malaise

Management: Blood transfusion if severe, supportive care. Self-limited (resolves in 7-10 days as anti-B19 antibodies develop)

2. Pregnancy Complications

Risk: Hydrops Fetalis & Fetal Loss

Overall risk if infected during pregnancy:
• Fetal loss: ~10% (highest in 2nd trimester)
• Hydrops fetalis: 3-9% (peak risk 13-20 weeks)

Mechanism: Fetal anemia → high-output cardiac failure → hydrops

Management of Pregnant Exposure:
1. Check maternal parvovirus IgG/IgM immediately
2. If IgG positive/IgM negative → Immune, no risk
3. If IgG negative or indeterminate → Recheck in 3-4 weeks
4. If acute infection confirmed → Serial ultrasounds for hydrops (weekly for 8-10 weeks)
5. If hydrops develops → Intrauterine blood transfusion (70-80% survival)

Note: NO congenital malformations associated with parvovirus B19 (unlike rubella)

3. Immunocompromised Patients

Risk: Chronic anemia (chronic persistent infection)
Mechanism: Cannot clear virus → ongoing RBC destruction
Presentation: Persistent anemia, no rash
Diagnosis: Positive parvovirus PCR, negative IgG/IgM (can't mount antibody response)
Treatment: IVIG 0.4 g/kg/day × 5-10 days (provides passive antibodies to clear virus)

4. Arthropathy

More common in adults (especially women)
Symmetric polyarthralgia/arthritis
Affects hands, wrists, knees, ankles
Can mimic rheumatoid arthritis
Self-limited, resolves in weeks to months (occasionally persists)
Treatment: NSAIDs

🔬Diagnosis

Clinical diagnosis sufficient in typical cases. Laboratory confirmation needed for: atypical presentations, aplastic crisis, pregnancy exposure, immunocompromised patients.

Laboratory Testing

Test	Timing/Result	Interpretation
Parvovirus B19 IgM	Positive for 2-3 months after infection	Acute or recent infection. Present when rash appears
Parvovirus B19 IgG	Appears shortly after IgM, persists lifelong	Current or past infection. Indicates immunity
Parvovirus B19 PCR (DNA)	Detects viral DNA	Active infection. Useful in immunocompromised (who may not make antibodies). Positive during aplastic crisis
CBC	If aplastic crisis suspected	Anemia, reticulocytopenia, normal WBC/platelets initially

Differential Diagnosis

Condition	Distinguishing Features
Rubella	Posterior cervical/occipital lymphadenopathy, different rash pattern
Measles	Koplik spots, cough/coryza/conjunctivitis, more severe illness
Scarlet fever	Sandpaper rash, strawberry tongue, positive Strep test
Roseola	Younger age, rash after fever resolves, no "slapped cheek"
Drug eruption	Medication history, different distribution
Systemic lupus	Butterfly rash (similar to slapped cheek), but systemic symptoms, positive ANA

💊Management

Treatment (Supportive for Uncomplicated Cases)

No specific antiviral therapy
Antipyretics/analgesics: Acetaminophen or ibuprofen for fever or arthralgias
Antihistamines: If rash is pruritic
Activity: As tolerated. Avoid triggers that exacerbate rash (sun, heat, exercise) if bothersome
Reassurance: Rash may come and go for weeks - this is normal

School/Daycare Exclusion NOT Needed: Once rash appears, child is no longer contagious. May attend school/daycare. Exclusion would not be helpful (most transmission occurs before diagnosis).

Special Situations - Treatment

Aplastic Crisis

Monitor CBC closely
Blood transfusion if symptomatic anemia or Hgb <5-6 g/dL
Supportive care
Isolate (respiratory precautions) until 7 days after illness onset

Chronic Infection (Immunocompromised)

IVIG (Intravenous Immunoglobulin)
Dose: 0.4 g/kg/day × 5-10 days
OR 1-2 g/kg as single dose or divided over 2-5 days
May need repeated courses if persistent viremia

Hydrops Fetalis

Maternal-fetal medicine consultation
Intrauterine blood transfusion
Close monitoring

🛡️ Prevention

No vaccine available
Hand hygiene: Reduces transmission
High-risk patients: Pregnant women, those with hemolytic anemias, immunocompromised should avoid exposure if possible
Healthcare workers: Standard and droplet precautions for hospitalized patients with aplastic crisis or chronic infection

References: Young NS, Brown KE. Parvovirus B19. NEJM. 2004;350(6):586-597. | CDC. Parvovirus B19 and Fifth Disease. 2023. | AAP. Red Book. 2021-2024.

🌹 Roseola Infantum (Sixth Disease)

📋Disease Overview

Key Characteristics

Causative Agent: Human Herpesvirus 6 (HHV-6), occasionally HHV-7

Transmission: Respiratory droplets, saliva

Incubation Period: 9-10 days (range: 5-15 days)

Contagious Period: During febrile phase (before rash)

Peak Age: 6-24 months (>90% by age 2 years)

Also Known As: Exanthem subitum, "roseola," "sixth disease," "baby measles"

Classic Presentation: High fever for 3-5 days in previously healthy infant, then fever abruptly resolves and rash appears. "Fever then rash" (versus "fever with rash" in most other exanthems).

Clinical Presentation

Phase 1: Febrile Phase (Days 1-5)

Hallmark: High fever out of proportion to appearance

Abrupt onset high fever: 39-40.5°C (103-105°F)
Child appears surprisingly well despite fever
Minimal respiratory symptoms (if any)
Mild irritability, decreased appetite
May have:

Edematous eyelids
Injected tympanic membranes (without otitis media)
Posterior cervical, occipital, postauricular lymphadenopathy
Nagayama spots (erythematous papules on soft palate/uvula)

Febrile seizures occur in 10-15% (highest risk of all childhood illnesses!)
Fever lasts 3-5 days, then abruptly resolves (defervescence)

Phase 2: Rash (Appears as fever resolves)

Key: Rash appears AFTER fever breaks (distinctive!)

Timing: Within 12-24 hours of fever resolution
Appearance: Rose-pink maculopapular eruption
Distribution: Starts on trunk/neck → spreads to face, proximal extremities
Characteristics:

Discrete lesions, 2-5 mm
Blanches with pressure
Not pruritic
Lesions may have pale halo

Duration: 1-3 days (rarely up to 1 week)
Resolution: Fades without desquamation
Child feels well, fever absent

Classic teaching: "When the fever breaks, the diagnosis is made"

📸 Clinical Images Reference:
Rash: Rose-pink, discrete maculopapular lesions
Distribution: Dense on trunk and neck, spreading to proximal extremities
Timing: Appears immediately after fever resolution

⚠️ Complications

Complication	Frequency	Notes
Febrile Seizures	10-15%	Most common complication. Often first presentation of illness. Simple febrile seizures typically (generalized, <15 min, single episode). Usually benign
Encephalitis/Meningoencephalitis	Rare	Can occur in immunocompetent children. Presents with prolonged altered mental status beyond typical post-ictal period
Myocarditis	Very rare	Case reports exist
Hepatitis	Uncommon	Mild transaminase elevation, usually subclinical
Thrombocytopenia	Rare	ITP-like picture
Severe disease in immunocompromised	Rare but serious	Bone marrow suppression, hepatitis, pneumonitis, encephalitis in transplant recipients

🔬Diagnosis

Clinical Diagnosis: Roseola is almost always diagnosed clinically. Laboratory testing rarely needed except to rule out other causes of fever in young infants or if atypical presentation.

Diagnostic Approach

Classic Presentation = Clinical diagnosis sufficient

Key Clues:
• Age 6-24 months
• High fever × 3-5 days
• Child appears well despite fever
• Fever abruptly resolves
• Rash appears AFTER fever breaks
• No toxic appearance

Laboratory Testing (When Needed)

Test	Indication	Finding
CBC	Fever workup in young infant	Leukopenia with relative lymphocytosis. Thrombocytopenia occasionally
HHV-6 IgM/IgG	Rarely needed, atypical cases	IgM positive in acute infection, IgG seroconversion
HHV-6 PCR	Complicated cases, immunocompromised	Detects viral DNA in blood, CSF
CSF studies	If febrile seizure was complex or concerning for meningitis	Usually normal or mild pleocytosis

Fever <3 months old: Requires careful evaluation to rule out serious bacterial infection (SBI). If roseola suspected but diagnosis not confirmed yet, may need sepsis workup depending on age and clinical appearance.

Differential Diagnosis

Measles: Fever WITH rash, cough/coryza/conjunctivitis, Koplik spots
Rubella: Fever WITH rash, lymphadenopathy pattern different, milder fever
Erythema infectiosum: "Slapped cheek," older age, lacy rash
Drug reaction: Medication history, fever may or may not resolve
Enteroviral infection: Variable, usually summer/fall
Serious bacterial infection: Toxic appearance, specific source identified

💊Management

Treatment (Supportive Only) Grade A

No specific antiviral therapy for immunocompetent children
Fever management:

Acetaminophen 10-15 mg/kg/dose PO/PR q4-6h
Ibuprofen 5-10 mg/kg/dose PO q6-8h (if >6 months)
Adequate hydration
Light clothing, room temperature environment

Reassurance: Explain natural course to parents
Activity: Rest as needed, activity as tolerated
No isolation required: After diagnosis established (rash phase)

🚨 Management of Febrile Seizures

Most febrile seizures in roseola are simple and benign.

Acute Management

During seizure:

Position on side (recovery position)
Protect from injury, remove nearby objects
Do NOT restrain or put anything in mouth
Time the seizure
If >5 minutes or status epilepticus: Benzodiazepine (lorazepam 0.1 mg/kg IV/IM or diazepam 0.2-0.5 mg/kg rectal)

Post-seizure:

Ensure airway patency
Monitor vital signs
Check temperature, administer antipyretic
Brief post-ictal period normal

Evaluation

Simple Febrile Seizure (most common in roseola):
• <15 minutes duration
• Generalized (not focal)
• Single episode in 24 hours
• Age 6 months - 5 years
• Rapid return to baseline

→ No neuroimaging or EEG needed
→ LP only if clinical suspicion of meningitis

Complex Febrile Seizure (requires further evaluation):
• >15 minutes
• Focal features
• Multiple episodes in 24 hours
• Prolonged post-ictal state

→ Consider LP, neuroimaging, neurology consultation

Parental Counseling

Febrile seizures are frightening but usually benign
Recurrence risk: ~30% overall, ~50% if age <12 months at first seizure
Does NOT cause brain damage or epilepsy in vast majority
Risk of epilepsy only slightly higher than general population (~1-2%)
Seizure action plan: What to do if happens again
No prophylactic anticonvulsants recommended for simple febrile seizures

Immunocompromised Patients

Ganciclovir or Foscarnet
For severe HHV-6 disease in transplant recipients or immunocompromised
Dose: Ganciclovir 5 mg/kg IV q12h
Duration: Based on clinical response and PCR negativity
Consult infectious diseases

🛡️ Prevention

No vaccine available
Hand hygiene to reduce transmission
Most children infected by age 2 - prevention not practical
After infection, lifelong latency (like all herpesviruses)

References: Zerr DM, et al. A population-based study of primary human herpesvirus 6 infection. NEJM. 2005;352(8):768-776. | AAP. Red Book. 2021-2024. | Subcommittee on Febrile Seizures. Febrile seizures: Guideline for the neurodiagnostic evaluation. Pediatrics. 2011;127(2):389-394.

💧 Varicella (Chickenpox)

📋Disease Overview

Key Characteristics

Causative Agent: Varicella-Zoster Virus (VZV) - Human Herpesvirus 3 (DNA virus)

Transmission: Highly contagious - airborne droplets and direct contact with lesions

Incubation Period: 10-21 days (average 14-16 days)

Contagious Period: 1-2 days before rash until ALL lesions crusted (usually 5-7 days)

Peak Age: 1-9 years (90% before age 15 in pre-vaccine era)

Seasonality: Late winter-early spring

Attack Rate: >90% in susceptible household contacts

Vaccine-Era Changes: Since universal varicella vaccination (1995 in US), incidence decreased >90%. "Breakthrough varicella" in vaccinated individuals is typically mild (50-100 lesions vs 250-500 in unvaccinated).

Classic Clinical Features

Hallmark Rash: "Dew drops on rose petals" - vesicles on erythematous base

Characteristic Pattern: Crops of lesions in different stages simultaneously

Distribution: Centripetal (trunk > face > extremities)

Evolution: Macule → Papule → Vesicle → Pustule → Crust (24-48h per lesion)

High-Risk Groups for Severe Disease:
• Neonates (maternal infection 5 days before to 2 days after delivery)
• Immunocompromised patients (malignancy, HIV, immunosuppressive therapy)
• Pregnant women (pneumonia risk 10-20%, congenital varicella syndrome)
• Adults (20× higher complication rate than children)
• Infants <12 months

🩺Clinical Presentation

Disease Course

Prodrome (0-2 days before rash)

Fever: 38-39°C (100.4-102.2°F), may be absent in children
Malaise, anorexia
Headache
Mild upper respiratory symptoms
More prominent in adults and adolescents

Rash - Day 1-2 (Characteristic!)

Evolution of Individual Lesions:

Macule (hours): Small red spot, 2-4 mm
Papule (hours): Raised, red
Vesicle (12-24h): Clear fluid-filled, "dewdrop on rose petal"
Pustule (24-48h): Cloudy fluid, may umbilicate
Crust (4-7 days): Scab forms, eventually falls off

Key: Multiple crops → lesions in ALL stages present simultaneously

Distribution Pattern

Centripetal: Trunk and face most dense
Spreads to scalp, mucous membranes (oral, conjunctival, genital)
Extremities less involved (opposite of smallpox - historical importance)
Lesions in hairline, scalp, mouth, and mucosa are characteristic

Number of Lesions

Unvaccinated: 250-500 lesions typically (range: 10-1500)
Breakthrough varicella (vaccinated): <50 lesions, often maculopapular without vesicles

Associated Symptoms

Pruritus (INTENSE!): Main symptom causing distress
Fever: Usually peaks at 38-39.5°C, lasts 2-4 days
Generally mild illness in healthy children

Resolution (1-3 weeks)

All lesions crusted by day 5-7 (no longer contagious)
Crusts fall off over 1-3 weeks
May leave temporary hypopigmentation or scarring (especially if scratched)

📸 Clinical Images Reference:
"Dewdrop on rose petal": Clear vesicle on erythematous base
Polymorphic: Macules, papules, vesicles, pustules, crusts all present
Distribution: Dense on trunk, scalp involvement, mucosal lesions

⚠️ Complications

Common Complications

Complication	Frequency	Notes
Secondary bacterial skin infections	5-10% (most common)	Group A Strep, S. aureus (including MRSA). Impetigo, cellulitis, abscess. Can progress to necrotizing fasciitis, toxic shock syndrome
Scarring	Common if scratched	Pitted scars, hypopigmentation
Pruritus	Nearly universal	Can be severe, leads to scratching and secondary infection

Serious Complications

Neurologic (1-3 per 10,000 cases):
• Cerebellar ataxia: Most common CNS complication (1:4,000), appears late in illness, usually self-limited
• Encephalitis: 1.7:100,000, mortality 5-10%, presents with altered mental status, seizures
• Meningitis: Rare
• Guillain-Barré syndrome, transverse myelitis, stroke: Rare

Complication	Details
Pneumonia	Viral (primary VZV) or bacterial superinfection. Higher risk: Adults (up to 20%), smokers, pregnant women, immunocompromised. Can be severe/fatal
Hepatitis	Mild transaminase elevation common, clinical hepatitis rare except immunocompromised
Thrombocytopenia	Usually mild, self-limited. Rarely severe bleeding
Reye syndrome	Rare now (avoid aspirin!). Encephalopathy + hepatic dysfunction
Death	2-3 per 100,000 cases (pre-vaccine). Now rare. Higher in immunocompromised, adults

Special Populations

Neonatal Varicella:
• If maternal infection 5 days before to 2 days after delivery → severe neonatal disease (mortality up to 30% if untreated)
• No maternal antibodies transferred → infant defenseless
• Treatment: VZIG + acyclovir

Congenital Varicella Syndrome (maternal infection <20 weeks):
• Risk: ~2% if infected in first 20 weeks
• Manifestations: Limb hypoplasia, cicatricial skin scarring, CNS abnormalities, eye defects (chorioretinitis, cataracts), low birth weight

Immunocompromised Patients:
• Progressive varicella: Prolonged eruption (weeks), visceral involvement (pneumonia, hepatitis, encephalitis)
• Mortality 7-14% if untreated
• Treatment: IV acyclovir

🔄 Herpes Zoster (Shingles) - Reactivation

VZV establishes latency in dorsal root ganglia after primary infection
Can reactivate years later as shingles
Dermatomal distribution, painful vesicular rash
More common with age, immunosuppression
Can occur in children, especially those who had varicella <1 year or breakthrough varicella

🔬Diagnosis

Clinical Diagnosis: Typical presentation is usually sufficient for diagnosis. Laboratory confirmation needed for: atypical presentations, immunocompromised patients, pregnant women, public health reporting, vaccine breakthrough cases.

Clinical Diagnosis

Classic Features:
• Vesicular rash (dewdrop on rose petal)
• Centripetal distribution
• Crops of lesions in multiple stages
• Scalp and mucosal involvement
• Appropriate epidemiology (contact history, seasonal)

Laboratory Confirmation

Test	Specimen	Timing/Notes
VZV PCR (Best)	Vesicular fluid, scab, CSF	Most sensitive and specific. Rapid results. Test of choice
Direct fluorescent antibody (DFA)	Vesicular scraping	Rapid (hours), less sensitive than PCR. Obtain vesicle base cells
Tzanck smear	Vesicular scraping	Shows multinucleated giant cells. Low sensitivity, cannot distinguish VZV from HSV. Rarely used now
Viral culture	Vesicular fluid	Slow (3-14 days), low sensitivity. Rarely used
VZV IgM/IgG	Serum	Acute IgM or 4-fold rise in IgG confirms infection. Less useful for diagnosis, more for immunity assessment

Differential Diagnosis

Disease	Key Distinguishing Features
Disseminated HSV	Immunocompromised, may have history of HSV, vesicles all same stage, PCR differentiates
Hand-foot-mouth disease	Characteristic distribution (hands, feet, mouth), no crops, not pruritic
Smallpox (historical)	Eradicated. Centrifugal (face/extremities > trunk), all lesions same stage, more severe prodrome
Impetigo	Honey-crusted lesions, no vesicles, positive bacterial culture
Insect bites	No crops, exposed areas, not on scalp/mucosa
Drug reaction	Medication history, different morphology usually
Stevens-Johnson syndrome	Target lesions, mucosal involvement more severe, systemic toxicity

💊Management

🏠 Supportive Care (Healthy Children) Grade A

Symptomatic Treatment

Antipyretics:

Acetaminophen 10-15 mg/kg/dose q4-6h
Ibuprofen 5-10 mg/kg/dose q6-8h (if >6 months)
⚠️ NEVER aspirin (Reye syndrome risk!)

Pruritus management (CRITICAL for preventing scratching/scarring):

Oral antihistamines: Diphenhydramine 1 mg/kg/dose q6h OR Hydroxyzine 0.5-1 mg/kg/dose q6h
Calamine lotion or oatmeal baths (lukewarm)
Keep fingernails short and clean
Cotton gloves at night for young children
Loose, comfortable clothing

Skin care:

Keep skin clean (daily gentle baths)
Avoid harsh soaps
Do NOT break vesicles

Oral care: Salt water rinses, soft foods if oral lesions painful
Hydration: Encourage fluids

💊 Antiviral Therapy - Acyclovir Grade B

General Principle: Antiviral therapy most effective if started within 24 hours of rash onset. Limited benefit if started >72 hours after rash.

Indications for Acyclovir in Children

MANDATORY Treatment (High Risk):
• Immunocompromised patients (any degree)
• Neonates
• Pregnant women
• Severe disease or complications (pneumonia, encephalitis, hepatitis)
→ Use IV acyclovir

High-Risk/Severe Disease - IV Acyclovir:
Dose: 10 mg/kg IV q8h (30 mg/kg/day) OR 500 mg/m² IV q8h
Duration: 7-10 days or until no new lesions for 48 hours
Hydration: Adequate IV fluids (prevent crystalluria)

Indications:
• Immunocompromised
• Neonatal varicella
• Varicella pneumonia
• Encephalitis
• Disseminated disease
• Pregnant women with severe disease

Consider Oral Acyclovir (Optional for lower risk)

Oral Acyclovir:
Dose: 20 mg/kg/dose (max 800 mg) PO QID × 5 days
Must start within 24 hours of rash for benefit

AAP recommends CONSIDERING for:
• Age >12 years (adolescents/adults have higher complication risk)
• Chronic cutaneous or pulmonary disorders
• Long-term salicylate therapy
• Short-term, intermittent, or aerosolized corticosteroids
• Secondary household cases (often more severe)

Effect: Modest reduction in duration and severity (1 day less fever, fewer lesions). Does NOT prevent complications significantly in healthy children.

NOT Routinely Recommended for: Healthy children <12 years with uncomplicated varicella. Supportive care is adequate. Cost and minimal benefit do not justify routine use.

🦠 Secondary Bacterial Infection Management

If Secondary Bacterial Infection Suspected/Confirmed:

Outpatient (Mild):
• Cephalexin 25-50 mg/kg/day divided q6-12h
• OR Amoxicillin-clavulanate 45 mg/kg/day divided q12h
• If MRSA risk: Clindamycin 30-40 mg/kg/day divided q6-8h OR TMP-SMX

Inpatient (Severe - cellulitis, abscess, sepsis):
• Vancomycin + Piperacillin-tazobactam
• OR Vancomycin + Ceftriaxone
• Surgical drainage if abscess

🛡️ Post-Exposure Prophylaxis Grade A

Exposure Definition: Household contact, face-to-face contact >5 minutes, or >1 hour in same indoor space with infectious person.

Option 1: Varicella Vaccine (Preferred if eligible)

Indications:
• Healthy, susceptible individuals ≥12 months
• No evidence of immunity
• No contraindications to vaccine

Timing: Within 3-5 days of exposure (optimal: 3 days)
Efficacy: 70-90% effective in preventing infection, >95% in preventing severe disease
Dose: 0.5 mL SC

Note: If breakthrough varicella occurs, typically mild

Option 2: Varicella-Zoster Immune Globulin (VZIG or VariZIG)

Indications (Cannot receive vaccine):
• Immunocompromised without evidence of immunity
• Newborns of mothers with varicella 5 days before to 2 days after delivery
• Hospitalized preterm infants ≥28 weeks (if mother no immunity) or <28 weeks regardless
• Pregnant women without evidence of immunity

Dose: 125 units (1 vial) per 10 kg IM (max 625 units / 5 vials)
Timing: Within 10 days of exposure (optimal: within 96 hours)
Effect: May prevent or attenuate disease. Does NOT provide long-term immunity

Option 3: Acyclovir Prophylaxis (Alternative if VZIG unavailable)

For high-risk patients if VZIG not available:
Acyclovir 40-80 mg/kg/day divided QID × 7 days
Start 7-10 days post-exposure
Less evidence than VZIG

🏥 Isolation Precautions

Airborne + Contact Precautions!
• Negative pressure room
• N95 respirator for susceptible healthcare workers
• Gown and gloves
• Duration: Until all lesions crusted
• Healthcare workers: Must have documented immunity
• Exclude from school/daycare until all lesions crusted (minimum 5 days after rash onset, usually 7 days)

💉 Vaccination (Prevention) Grade A

Routine Childhood Schedule (CDC/AAP):
Dose 1: 12-15 months
Dose 2: 4-6 years
(Catch-up: 2 doses ≥3 months apart if needed)

Efficacy: 70-90% prevention of any disease, >95% prevention of severe disease after 2 doses
Duration: Long-lasting, probably lifelong
Impact: >90% reduction in disease incidence since universal vaccination

Contraindications:
• Severe immunodeficiency
• Pregnancy
• Recent immunoglobulin administration
• Severe allergic reaction to vaccine component

Special Populations:
• HIV-infected children with CD4% ≥15% can receive vaccine
• Household contacts of immunocompromised should be vaccinated
• Healthcare workers must be immune (2 doses or evidence of immunity)

References: AAP. Red Book. 2021-2024. | CDC. Prevention of Varicella: Recommendations of ACIP. MMWR. 2007;56(RR-4):1-40. | Marin M, et al. Prevention of Varicella: Updated ACIP Recommendations. MMWR. 2007.

🦠 Scarlet Fever (Scarlatina)

📋Disease Overview

Key Characteristics

Causative Agent: Group A β-hemolytic Streptococcus (Streptococcus pyogenes) producing erythrogenic toxins

Mechanism: Pharyngitis PLUS exotoxin (streptococcal pyrogenic exotoxins A, B, C) → rash

Transmission: Respiratory droplets, direct contact

Incubation Period: 2-5 days (12 hours to 7 days)

Contagious Period: Until 24 hours after starting antibiotics (or 2-3 weeks if untreated)

Peak Age: 5-15 years (rare <3 years, rare in adults)

Seasonality: Late fall, winter, early spring

Key Concept: Scarlet fever = Strep pharyngitis + erythrogenic toxin-mediated rash. Not all Group A Strep strains produce toxin, so not all strep throat leads to scarlet fever. Individual must also lack immunity to the specific toxin.

Classic Clinical Triad

1. Pharyngitis: Red, inflamed throat with exudate, palatal petechiae

2. "Strawberry Tongue": White coating → red with prominent papillae

3. "Sandpaper" Rash: Diffuse erythema with fine papules, blanches with pressure

Importance of Treatment: Untreated Group A Strep can lead to:
• Acute rheumatic fever (ARF) - 3% risk if untreated
• Post-streptococcal glomerulonephritis (PSGN)
• Suppurative complications (peritonsillar abscess, retropharyngeal abscess, cervical lymphadenitis)
• Invasive disease (bacteremia, necrotizing fasciitis, toxic shock syndrome)

Antibiotics prevent ARF but NOT PSGN

🩺Clinical Presentation

Disease Course

Prodrome/Onset (Day 1-2)

Pharyngitis Symptoms:

Fever: Abrupt onset, 38.3-40°C (101-104°F)
Severe sore throat
Headache, malaise
Nausea, vomiting, abdominal pain (especially young children)
Chills
Odynophagia (painful swallowing)

Rash Appearance (12-48 hours after fever)

Characteristic "Sandpaper" Rash:

Texture: Fine, rough papules on erythematous base ("goose bumps on sunburn," "sandpaper texture")
Color: Bright red, blanches with pressure
Distribution:

Starts: Neck, chest, axillae, groin (flexural areas)
Spreads: Trunk → extremities (centrifugal) within 24 hours
Dense in skin folds (Pastia lines - linear petechiae in antecubital fossae, axillae, groin)

Facial involvement:

Flushed cheeks
Circumoral pallor (pale area around mouth) - CHARACTERISTIC!

Duration: 4-5 days, then fades

Oropharyngeal Findings (Appear early, persist)

Pharyngeal erythema: Beefy red throat
Tonsillar exudate: White/yellow patches (in 50-90%)
Palatal petechiae: Small red spots on soft palate (SPECIFIC for Strep!)
"Strawberry tongue":

White strawberry (Days 1-2): White coating with red, prominent papillae
Red strawberry (Days 4-5): Coating sheds → bright red tongue with prominent papillae

Tender anterior cervical lymphadenopathy

Desquamation Phase (Week 2-3)

Begins: 7-10 days after rash onset (as rash fades)
Pattern: Fine, flaky peeling → coarse, sheet-like peeling
Distribution: Same as rash (face → trunk → extremities)
Prominent on: Fingertips, toes, palms, soles
Duration: Can last 2-3 weeks
Characteristic feature! - helps confirm retrospective diagnosis

📸 Clinical Images Reference:
Sandpaper rash: Fine papules on erythematous background
Pastia lines: Linear petechiae in skin folds
Circumoral pallor: Pale area around mouth with flushed cheeks
Strawberry tongue: Red with prominent papillae
Desquamation: Sheet-like peeling of hands and feet

Key Distinguishing Features (Diagnosis Clues)

Feature	Description	Significance
Pastia lines	Transverse red lines in antecubital, axillary, inguinal creases	Specific for scarlet fever, may persist after rash fades
Circumoral pallor	Pale area around mouth contrasting with flushed face	Highly characteristic
Palatal petechiae	Pinpoint red spots on soft palate	Specific for Group A Strep
Desquamation	Sheet-like peeling 1-2 weeks after rash	Confirms diagnosis retrospectively

⚠️ Complications

Suppurative (Early) Complications

Complication	Timing	Features
Peritonsillar abscess	During acute illness	Worsening throat pain, trismus, uvular deviation, muffled voice
Retropharyngeal abscess	During acute illness	Drooling, neck stiffness, respiratory distress
Cervical lymphadenitis	During acute illness	Tender, enlarged lymph nodes, may suppurate
Otitis media, sinusitis	During/after acute illness	Secondary bacterial infection
Bacteremia/Sepsis	During acute illness	Rare, toxic appearance

Non-Suppurative (Late) Complications

Acute Rheumatic Fever (ARF):
• Onset: 2-4 weeks after pharyngitis
• Risk: ~3% if untreated pharyngitis, <1% in developed countries with treatment
• Manifestations: Carditis (most serious), polyarthritis, chorea, erythema marginatum, subcutaneous nodules
• Jones Criteria for diagnosis
• Prevention: Appropriate antibiotic treatment of pharyngitis
• Long-term sequela: Rheumatic heart disease

Post-Streptococcal Glomerulonephritis (PSGN):
• Onset: 1-3 weeks after pharyngitis (or 3-6 weeks after skin infection)
• Manifestations: Hematuria, proteinuria, edema, hypertension, oliguria
• Usually self-limited
• Antibiotics do NOT prevent PSGN (unlike ARF)
• Only certain nephritogenic strains cause PSGN

Other Complications	Details
Toxic shock-like syndrome	Streptococcal TSS: Hypotension, multiorgan failure. Rare but life-threatening
Necrotizing fasciitis	Invasive soft tissue infection. Surgical emergency
PANDAS	Pediatric Autoimmune Neuropsychiatric Disorders Associated with Strep. Controversial

🔬Diagnosis

Diagnosis Requires: Clinical features PLUS laboratory confirmation of Group A Strep. Cannot diagnose by clinical features alone (many viruses can mimic).

Diagnostic Approach

Clinical Suspicion Based On:
• Sudden onset fever + sore throat
• Sandpaper rash with circumoral pallor
• Strawberry tongue
• Palatal petechiae
• Tender cervical lymphadenopathy
• Age 5-15 years (peak incidence)
• Winter-spring season

Laboratory Confirmation Grade A

Test	Timing	Sensitivity/Specificity	Notes
Rapid Antigen Detection Test (RADT)	Results in minutes	Sensitivity: 70-90% Specificity: 95-99%	If positive → treat. If negative in child/adolescent → back up with culture. High specificity means false positives rare
Throat Culture	24-48 hours	Sensitivity: 90-95% Specificity: 95-99%	Gold standard. Use if RADT negative in child. Not needed to confirm positive RADT

AAP/IDSA Recommendations:
• Children/Adolescents: If RADT negative → back up with culture
• Adults: RADT alone sufficient (lower prevalence of Strep, lower ARF risk)
• Positive RADT → treat, no culture needed
• Do NOT test/treat asymptomatic contacts (except outbreak situations)
• Do NOT perform "test of cure" after treatment

Additional Laboratory Findings

Test	Finding	Use
CBC	Leukocytosis with neutrophilia, eosinophilia during recovery	Not diagnostic, rarely needed
ASO titer (Anti-streptolysin O)	Rises 3-6 weeks after infection	NOT for acute diagnosis. Used to confirm recent Strep infection when evaluating for ARF or PSGN
Anti-DNase B	Rises after Strep infection	More sensitive than ASO for skin infections. Used for ARF/PSGN evaluation

Differential Diagnosis

Disease	Key Distinguishing Features
Viral pharyngitis	Coryza, cough, conjunctivitis, diarrhea present. No exudate typically. Negative Strep test
Measles	Koplik spots, cough/coryza/conjunctivitis prominent, different rash pattern (maculopapular, confluent)
Rubella	Posterior cervical lymphadenopathy, milder illness, no throat findings
Kawasaki disease	≥5 days fever, conjunctivitis, extremity changes, no response to antibiotics. Negative Strep test
Staphylococcal toxic shock syndrome	Hypotension, multiorgan involvement, different rash (diffuse erythroderma), desquamation of palms/soles
Drug eruption	Medication history (especially ampicillin/amoxicillin if given for presumed pharyngitis)
Infectious mononucleosis	Posterior cervical lymphadenopathy, splenomegaly, prolonged fever, atypical lymphocytes, positive Monospot/EBV serology

Modified Centor Criteria (Clinical Prediction for Strep Pharyngitis)

Used to determine when to test for Strep (NOT for diagnosis without testing!)

Criterion	Points
Tonsillar exudate	+1
Tender anterior cervical lymphadenopathy	+1
Fever (by history)	+1
Absence of cough	+1
Age 3-14 years	+1
Age 15-44 years	0
Age ≥45 years	-1

Interpretation:
Score 0-1: No testing, no antibiotics (2-23% Strep probability)
Score 2-3: Perform RADT ± culture (28-35% Strep probability)
Score 4-5: Perform RADT ± culture or empiric treatment (52% Strep probability)

💊Treatment & Management

Goals of Treatment:
• Prevent acute rheumatic fever (ARF)
• Reduce symptoms and shorten illness duration
• Prevent suppurative complications
• Reduce transmission

ARF Prevention: Effective if antibiotics started within 9 days of symptom onset

💊 Antibiotic Therapy Grade A

First-Line: Penicillin (Drug of Choice)

Penicillin V (Oral - Preferred for adherence):
Children: 250 mg PO BID or TID × 10 days (if <27 kg)
Children/Adolescents: 500 mg PO BID or TID × 10 days (if ≥27 kg)

Benzathine Penicillin G (IM - Best for adherence concerns):
<27 kg: 600,000 units IM × 1 dose
≥27 kg: 1.2 million units IM × 1 dose

Advantages: Narrow spectrum, low cost, effective, no resistance
IM preferred if: Concern for adherence, history of ARF, rheumatic heart disease

Alternative: Amoxicillin

Amoxicillin:
50 mg/kg once daily (max 1000 mg) × 10 days
OR 25 mg/kg BID (max 500 mg/dose) × 10 days

Advantage: Better taste than penicillin V, once-daily dosing option improves adherence
Equivalent efficacy to penicillin

Penicillin-Allergic (Non-IgE mediated)

Cephalexin:
20 mg/kg/dose BID (max 500 mg/dose) × 10 days

Cefadroxil:
30 mg/kg once daily (max 1 g) × 10 days

Note: Can use cephalosporins if non-severe penicillin allergy (no anaphylaxis)

Penicillin-Allergic (IgE-mediated/Anaphylaxis)

Azithromycin:
12 mg/kg once daily (max 500 mg) × 5 days

Clarithromycin:
15 mg/kg/day divided BID (max 250 mg/dose) × 10 days

Clindamycin:
20 mg/kg/day divided TID (max 300 mg/dose) × 10 days

Note: Resistance to macrolides increasing (5-15% in US, higher in some areas). Check local resistance patterns

CRITICAL:
• 10 days of therapy required for all oral agents (except azithromycin 5 days) to eradicate Strep and prevent ARF
• Shorter courses NOT adequate
• Emphasize adherence to full course
• Tetracyclines and sulfonamides should NOT be used (not effective for eradication)

🏠 Supportive Care

Antipyretics/Analgesics:

Acetaminophen 10-15 mg/kg/dose q4-6h
Ibuprofen 5-10 mg/kg/dose q6-8h

Throat comfort measures:

Warm saltwater gargles
Throat lozenges (if age-appropriate)
Cold/frozen treats (popsicles, ice cream)
Soft foods

Hydration: Encourage fluids
Rest: Activity as tolerated

🏥 When to Seek Further Care

Return immediately if:
• Difficulty breathing
• Drooling, unable to swallow
• Severe neck pain or stiffness
• Muffled voice (suggests abscess)
• Signs of dehydration
• No improvement after 48 hours of antibiotics
• Worsening symptoms after initial improvement
• Dark/tea-colored urine, edema (suggests PSGN)

🏫 School/Daycare Exclusion

Return to school/daycare:
• After 24 hours of antibiotics
• AND fever-free without antipyretics
• AND feeling well enough to participate

Untreated: Contagious for 2-3 weeks (should not attend)

👨‍👩‍👧‍👦 Management of Contacts

Generally: No testing or treatment of asymptomatic household contacts
Exceptions (consider testing/treating contacts):

History of ARF or rheumatic heart disease in family
Multiple cases in household (ping-pong transmission)
Outbreak in closed community
Presence of person at high risk for ARF complications

🔁 Recurrent/Persistent Strep Pharyngitis

True Treatment Failure (Rare)

Persistent symptoms with positive culture/RADT after full antibiotic course
Options:

Retreat with same antibiotic (check adherence)
IM benzathine penicillin G (ensures full treatment)
β-lactamase stable antibiotic (amoxicillin-clavulanate, cephalosporin, clindamycin)

Strep Carrier (Common - 10-15% of children)

Positive Strep test but symptoms from concurrent viral illness
Chronic carriage without illness
Do NOT repeatedly treat carriers
Consider if:

Repeatedly positive tests without symptoms
Personal or family history of ARF → may need treatment
Otherwise, reassure and do not test when asymptomatic

True Recurrence (Multiple Symptomatic Episodes)

Multiple documented Strep infections with symptoms
Consider:

Different Strep strains (not treatment failure)
Household contact screening/treatment
ENT referral if >6-7 episodes/year (tonsillectomy consideration)

🛡️ Prevention

No vaccine available
Hand hygiene: Most important prevention measure
Avoid sharing utensils, drinks, personal items
Replace toothbrush after 24 hours of antibiotics
Secondary prophylaxis: Only for history of ARF (long-term penicillin to prevent recurrence)

References: Shulman ST, et al. Clinical Practice Guideline for Diagnosis and Management of Group A Streptococcal Pharyngitis: 2012 Update by IDSA. Clin Infect Dis. 2012;55(10):e86-e102. | AAP. Red Book. 2021-2024. | Gerber MA, et al. Prevention of Rheumatic Fever and Diagnosis/Treatment of Acute Streptococcal Pharyngitis: AHA Scientific Statement. Circulation. 2009;119(11):1541-1551.

✋ Hand-Foot-Mouth Disease (HFMD)

📋Disease Overview

Key Characteristics

Causative Agents:
• Coxsackievirus A16 (most common, typically mild)
• Enterovirus 71 (EV71) - can cause severe neurologic complications
• Other enteroviruses: Coxsackie A6, A10, B2, B5

Transmission: Fecal-oral route (primary), respiratory droplets, direct contact with vesicle fluid

Incubation Period: 3-7 days (range: 3-10 days)

Contagious Period: During first week of illness (but virus can shed in stool for weeks to months)

Peak Age: <5 years (especially 6 months - 3 years)

Seasonality: Summer and fall in temperate climates, year-round in tropics

Highly Contagious: Common in daycare and school settings. Outbreaks frequently occur. Adults can get HFMD (often from caring for infected children), though less common and usually milder.

Classic Presentation

Characteristic Distribution: Vesicles/ulcers in mouth + vesicular rash on hands, feet (and sometimes buttocks)

Typical Course: Mild fever → oral lesions (painful!) → peripheral rash

Self-Limited: Usually resolves in 7-10 days without complications

Enterovirus 71 (EV71) - Severe Variant:
More common in Asia-Pacific region, can cause:
• Severe neurologic complications (encephalitis, meningitis, poliomyelitis-like paralysis)
• Cardiopulmonary failure
• Death (mortality 10-25% in severe cases)
• Predominantly affects children <5 years
• Red flags: Persistent high fever, vomiting, myoclonic jerks, ataxia, cranial nerve palsies, cardiorespiratory compromise

🩺Clinical Presentation

Disease Course - Classic (Coxsackie A16)

Prodrome (Days 1-2)

Low-grade fever: 38-39°C (100.4-102.2°F), lasts 1-2 days
Malaise, irritability
Sore throat
Decreased appetite
Sometimes absent - rash may be first sign

Oral Lesions (Days 1-3, MOST DISTRESSING)

Enanthem (appears first, before exanthem):

Location: Tongue, buccal mucosa, gingiva, hard/soft palate
Evolution:

Begin as small red papules (1-2 mm)
Progress to vesicles
Rupture quickly → shallow, painful ulcers with yellow-gray base and red halo

Number: Usually 5-10 lesions (can be more)
Symptoms: VERY PAINFUL - difficulty eating/drinking, drooling
Duration: 5-7 days

Peripheral Rash (Days 1-2, appears with or shortly after oral lesions)

Exanthem - Characteristic Distribution:

Classic locations:

Hands: Palms, fingers (especially lateral aspects and between fingers)
Feet: Soles, toes, heel
Buttocks: Common, especially in infants/toddlers

Appearance:

Begin as flat red spots (macules)
Evolve to raised papules
Form vesicles (oval/elliptical, 2-10 mm)
Vesicles on erythematous base
"Football-shaped" or elongated vesicles (characteristic!)

Number: Variable - few to hundreds
Characteristics:

Usually NOT pruritic (unlike varicella)
Tender but less painful than oral lesions
Do not rupture easily

Duration: 7-10 days, heal without scarring

📸 Clinical Images Reference:
Oral lesions: Small vesicles/ulcers on tongue, buccal mucosa
Hand rash: Oval vesicles on palms, lateral fingers
Foot rash: Vesicles on soles, between toes
Buttock rash: Vesicles/papules on buttocks (infant presentation)

⚡ Atypical Presentations

Coxsackie A6 (Increasingly Common)

More Severe Cutaneous Disease:
• Widespread vesiculobullous rash (may resemble varicella)
• Involves trunk, extremities, face (not just hands/feet)
• Larger vesicles, more numerous lesions
• May have bullae
• Can be quite pruritic
• Onychomadesis (nail shedding) in 4-6 weeks - Common sequela! (20-50% of cases)
• Desquamation of hands/feet during recovery

Herpangina (Enterovirus-related)

Same viral family, different presentation
Vesicles/ulcers LIMITED to posterior oropharynx (soft palate, uvula, tonsillar pillars)
NO peripheral rash
High fever, sore throat, difficulty swallowing
Consider part of HFMD spectrum

Eczema Coxsackium

HFMD in children with atopic dermatitis
Vesicles concentrated in areas of eczema
Can be more extensive

⚠️ Complications

Common/Mild Complications

Complication	Details
Dehydration	Most common. Due to painful oral lesions → refusal to drink. May require IV fluids
Onychomadesis	Nail shedding 4-6 weeks after illness. More common with Coxsackie A6. Benign, nails regrow normally
Desquamation	Peeling of hands/feet during recovery. Coxsackie A6 especially

Severe Complications (Primarily EV71)

Neurologic (EV71, rare with other strains):
• Aseptic meningitis: Most common neurologic complication
• Brainstem encephalitis: Myoclonic jerks, tremor, ataxia, cranial nerve palsies
• Acute flaccid paralysis: Polio-like syndrome, permanent paralysis possible
• Encephalitis: Altered mental status, seizures
• Autonomic nervous system dysregulation: Can progress to cardiopulmonary failure

Cardiopulmonary:
• Myocarditis, pulmonary edema/hemorrhage
• Neurogenic shock
• Leading cause of death in severe EV71 infection

Warning Signs (Seek immediate care):
• Persistent high fever (>39°C for >48 hours)
• Persistent vomiting
• Myoclonic jerks or tremor
• Ataxia, weakness
• Altered consciousness, lethargy
• Rapid breathing, respiratory distress
• Cold extremities, poor perfusion
• Age <3 years with concerning symptoms

🔬Diagnosis

Clinical Diagnosis: Typical HFMD is diagnosed clinically. Laboratory testing rarely needed except for severe cases, outbreak investigation, or atypical presentations.

Clinical Diagnosis Criteria

Typical Features:
• Oral ulcers/vesicles (tongue, buccal mucosa)
• Peripheral vesicular rash (hands, feet, ± buttocks)
• Age <5 years
• Summer-fall season (or known outbreak)
• Mild illness, self-limited course
• No alternative diagnosis

Laboratory Testing (When Indicated)

Test	Specimen	Use
Enterovirus PCR	Throat swab, rectal swab, stool, CSF, vesicle fluid	Most sensitive. Identifies enterovirus. Can subtype to identify EV71. Use for severe cases, CNS involvement, outbreak investigation
Viral culture	Throat swab, stool, vesicle fluid	Less sensitive, slow (days to weeks). Allows serotyping but rarely used clinically
Serology (IgM, IgG)	Serum	Retrospective diagnosis, epidemiologic studies. Not for acute diagnosis
CSF studies	CSF	If meningitis/encephalitis suspected. Typically shows lymphocytic pleocytosis, normal glucose, mild protein elevation. Enterovirus PCR on CSF

Differential Diagnosis

Disease	Key Distinguishing Features
Herpetic gingivostomatitis (HSV-1)	More severe oral involvement (gums, lips), high fever, no peripheral rash, vesicles typically on lips/perioral area. PCR differentiates
Varicella	Centripetal distribution, lesions in multiple stages (crops), very pruritic, scalp involvement
Aphthous stomatitis	Recurrent, no rash, no fever, painful oral ulcers only
Erythema multiforme	Target lesions, more severe mucosal involvement, different distribution, may have drug history
Stevens-Johnson syndrome	Severe systemic toxicity, extensive mucosal involvement, bullae, medication history typically
Herpes zoster	Dermatomal distribution, more painful, typically unilateral
Scabies	Very pruritic, burrows, webspace involvement, no oral lesions

💊Management

No Specific Antiviral Treatment: Management is entirely supportive. Focus on hydration, pain control, and monitoring for complications.

🏠 Supportive Care (Mainstay of Treatment) Grade A

Pain Management - CRITICAL!

Systemic Analgesics:
• Acetaminophen 10-15 mg/kg/dose PO q4-6h
• Ibuprofen 5-10 mg/kg/dose PO q6-8h (if >6 months)
• Alternate acetaminophen and ibuprofen for breakthrough pain
• ⚠️ AVOID aspirin (Reye syndrome risk with viral illness)

Oral Pain Relief (Essential for maintaining hydration)

"Magic Mouthwash" - Various Formulations:

Option 1: Diphenhydramine + Antacid
• Liquid diphenhydramine + liquid antacid (Maalox/Mylanta) 1:1
• Swish and spit (or swallow if <6 years) before meals
• Use sparingly (risk of systemic absorption in young children)

Option 2: Viscous Lidocaine 2%
• Age >4 years only
• Apply to oral lesions with cotton swab
• Max: 1.5 mg/kg/dose q3-4h (max 4.5 mg/kg/day)
• ⚠️ Caution: Can cause numbness → aspiration risk, systemic toxicity if overused

Option 3: Over-the-counter oral gels
• Orajel, Anbesol (benzocaine) - use caution in infants
• Glycerin-based products

⚠️ Avoid: Acidic, spicy, salty, or rough-textured foods (aggravate pain)

Hydration (MOST IMPORTANT!)

Encourage cold/cool fluids (better tolerated than warm)
Best choices:

Popsicles, ice cream, frozen treats (soothing AND hydrating)
Cold milk, smoothies
Cool water
Oral rehydration solutions

Avoid: Citrus juices, carbonated beverages (acidic, painful)
Small, frequent sips better tolerated than large amounts
Premedicate with analgesics 30 min before meals

Signs of Dehydration (Hospitalization Criteria):
• Decreased urine output (<3 wet diapers/day, <1-2 voids/day in older children)
• Dry mucous membranes
• No tears when crying
• Sunken fontanelle (infants)
• Lethargy
• → May need IV hydration

Skin Care

Keep lesions clean and dry
Avoid scratching or picking (can cause secondary infection)
Loose, comfortable clothing
Usually not pruritic, so antihistamines not typically needed
No special creams/ointments needed - lesions heal spontaneously

🏥 When to Seek Medical Care

Seek Immediate Care If:
• Signs of dehydration (see above)
• Inability to drink or maintain hydration
• High fever >39°C (102.2°F) for >48 hours
• Persistent vomiting
• Severe headache
• Neck stiffness
• Altered mental status, lethargy, difficult to arouse
• Myoclonic jerks, tremor, ataxia, weakness
• Difficulty breathing, rapid breathing
• Cold extremities, poor perfusion
• Age <3 months with any fever
• Immunocompromised patient

Indications for Hospitalization

Dehydration requiring IV fluids
CNS involvement (meningitis, encephalitis)
Cardiopulmonary complications
Severe pain uncontrolled with oral medications
Inability to maintain oral intake
Suspected EV71 with risk factors

🏫 School/Daycare Exclusion

AAP Recommendations:
• Exclusion NOT required for uncomplicated HFMD
• Child may return when:
  - Fever-free
  - Oral lesions have healed enough to eat/drink
  - Able to participate in activities
  - No drooling (from uncontrolled oral lesions)

Note: Prolonged viral shedding in stool (weeks to months) means complete elimination of transmission impossible. Focus on symptom control and hygiene rather than strict exclusion.

🛡️ Prevention & Infection Control

Hand hygiene (MOST IMPORTANT!):

Frequent handwashing with soap and water (alcohol-based gels less effective against enteroviruses)
Especially after diaper changes, toilet use, before meals
Clean surfaces and toys regularly

Respiratory hygiene:

Cover coughs and sneezes
Avoid sharing utensils, cups, towels

Diaper changing precautions:

Careful disposal of diapers
Clean changing areas thoroughly
Hand hygiene after changing

Avoid contact with vesicle fluid
Disinfection: Bleach-based cleaners (0.5% sodium hypochlorite) for surfaces

Vaccine Status:
• No vaccine available in Western countries
• EV71 vaccines available in China (licensed 2016) - shown to be effective
• Vaccines under development for broader use

📋 Patient/Parent Education

HFMD is common, highly contagious viral illness
Usually mild and self-limited (7-10 days)
Focus on keeping child comfortable and hydrated
Pain is worst in first 3-5 days, then improves
Nail shedding may occur 4-6 weeks later (benign, nails regrow)
No specific treatment or cure available
Child can return to activities when feeling better and able to eat/drink
Siblings/family members likely to get it (very contagious)
Adults can get HFMD too (from caring for infected children)
Good hand hygiene most important prevention

References: AAP. Red Book. 2021-2024. | CDC. Hand, Foot, and Mouth Disease (HFMD). 2023. | Esposito S, Principi N. Hand, foot and mouth disease: current knowledge on clinical manifestations, epidemiology, aetiology and prevention. Eur J Clin Microbiol Infect Dis. 2018;37(3):391-398.

❤️ Kawasaki Disease

📋Disease Overview

Key Characteristics

Definition: Acute, self-limited systemic vasculitis of medium-sized arteries, particularly coronary arteries

Also Known As: Mucocutaneous lymph node syndrome

Etiology: Unknown (likely infectious trigger in genetically susceptible host)

Peak Age: 6 months - 5 years (80% <5 years, peak 18-24 months)

Gender: Male > Female (1.5:1)

Ethnicity: Highest incidence in children of Asian descent (especially Japanese), but affects all races

Seasonality: Winter and spring peaks in temperate climates

CRITICAL IMPORTANCE: Kawasaki disease is the leading cause of acquired heart disease in children in developed countries. Without treatment, 15-25% develop coronary artery aneurysms. Early recognition and treatment (within 10 days) reduces this risk to <5%.

This is a medical emergency requiring urgent treatment!

2017 AHA Diagnostic Criteria Grade A

Classic (Complete) Kawasaki Disease:
Fever ≥5 days PLUS ≥4 of 5 principal clinical features

Incomplete (Atypical) Kawasaki Disease:
Fever ≥5 days PLUS 2-3 principal features + supportive laboratory/echo findings

REQUIRED Criterion

Fever: ≥38.5°C (101.3°F) for ≥5 days*
*Treatment can be initiated before day 5 if other criteria met + evidence of systemic inflammation

Principal Clinical Features (Need ≥4 of 5)

1. Bilateral bulbar conjunctival injection (non-purulent)
• Limbic sparing (white ring around iris)
• No exudate or discharge
• Usually painless

2. Oral mucous membrane changes
• Erythema, cracked/fissured lips
• "Strawberry tongue" (red with prominent papillae)
• Diffuse erythema of oral and pharyngeal mucosa

3. Peripheral extremity changes
Acute phase: Erythema of palms/soles, indurative edema of hands/feet
Subacute phase (weeks 2-3): Desquamation (peeling) starting from periungual regions

4. Polymorphous rash
• Primarily on trunk
• Maculopapular, diffuse erythroderma, or erythema multiforme-like
• NOT vesicular or bullous
• May be accentuated in perineal area (early desquamation)

5. Cervical lymphadenopathy
• Usually unilateral
• ≥1.5 cm diameter
• Least common of the principal features (~50%)

Important Notes:
• Patients with ≥4 principal features can be diagnosed on day 4 of fever (don't have to wait 5 days if classic presentation)
• Patients meeting criteria cannot be explained by another disease process
• Experienced clinicians may diagnose with fever + <4 criteria if echocardiogram shows coronary artery abnormalities

Incomplete (Atypical) Kawasaki Disease

High Index of Suspicion Needed! More common in:
• Infants <6 months (highest risk for coronary complications!)
• Older children >5 years

Diagnosis: Fever ≥5 days + 2-3 principal criteria + laboratory/echo findings suggesting systemic inflammation and coronary involvement

Supplemental Laboratory Criteria

Classic Finding	Supportive Value
CRP ≥3.0 mg/dL OR ESR ≥40 mm/hr	Consistent with systemic inflammation
Albumin ≤3.0 g/dL	Common
Anemia for age	Normocytic, normochromic
Elevated ALT	Mild hepatic involvement
Platelets ≥450,000 after day 7	Thrombocytosis (may not be present early)
WBC ≥15,000/mm³	Leukocytosis common
Sterile pyuria (≥10 WBC/hpf)	Urethritis from vasculitis

Algorithm for Incomplete KD (AHA):
If infant <6 months with fever ≥7 days + elevated CRP/ESR → Get echo even without clinical features
If fever ≥5 days + 2-3 features + CRP ≥3.0 or ESR ≥40 → Get echo + supplemental labs
If ≥3 supplemental lab criteria positive OR echo shows coronary changes → Treat as KD

🩺Clinical Features & Course

Three Phases of Kawasaki Disease

Acute Febrile Phase (Days 1-11)

Hallmark: High fever + principal clinical features

Fever: Abrupt onset, high (39-40°C), persistent, unresponsive to antipyretics, lasts 1-2 weeks if untreated
Extreme irritability (very prominent - inconsolable crying, out of proportion to physical findings)
Principal clinical features (appear sequentially, not all at once):

Conjunctivitis (Days 1-5)
Oral changes (Days 2-5)
Rash (Days 3-5)
Extremity changes (Days 3-7)
Lymphadenopathy (variable timing)

Additional findings:

BCG reactivation site redness (in BCG-vaccinated populations) - specific!
Arthralgia/arthritis (small and large joints)
Aseptic meningitis (CSF pleocytosis in 50%)
Diarrhea, vomiting, abdominal pain
Gallbladder hydrops
Hepatitis (mild ALT elevation)
Urethritis (sterile pyuria)
Anterior uveitis (on slit lamp, not clinically apparent)

Subacute Phase (Days 11-21)

Fever resolves, desquamation begins, highest risk for coronary aneurysms

Fever defervesces
Periungual desquamation (starts at fingertips, progresses to entire hand/foot) - CLASSIC!
Thrombocytosis (peaks week 2-3, can be >1 million/mm³)
Irritability persists but improves
Arthritis may develop or worsen
Coronary aneurysms develop (if occur, typically weeks 2-4)
Persistent elevated inflammatory markers

Convalescent Phase (Days 21-60+)

Clinical signs resolve, inflammatory markers normalize

All clinical signs gradually disappear
Deep transverse grooves on nails (Beau lines) - may appear 1-2 months later
ESR, CRP normalize (may take 6-8 weeks)
Thrombocytosis resolves
Coronary aneurysms: May remain, regress, or rarely progress

📸 Clinical Images Reference:
Conjunctivitis: Bilateral non-purulent injection with limbic sparing
Oral changes: Erythematous cracked lips, strawberry tongue
Extremity changes: Erythema and edema of hands/feet (acute); periungual desquamation (subacute)
Rash: Polymorphous eruption, perineal early desquamation
Lymphadenopathy: Unilateral cervical node ≥1.5 cm

⚠️ Cardiac Complications (MOST IMPORTANT!)

Coronary Artery Aneurysms (CAAs):
• Without treatment: 15-25% of patients
• With IVIG + aspirin within 10 days: <5%
• With IVIG + aspirin after 10 days: 10-15%
• Highest risk: Infants <6 months, delayed diagnosis/treatment

Classification by Size (Z-score preferred):
• Small: <5 mm internal diameter
• Medium: 5-8 mm
• Giant (highest risk): ≥8 mm

Natural History:
• 50-67% of small/medium aneurysms regress within 1-2 years (remodeling)
• Giant aneurysms rarely regress
• Risk of thrombosis, stenosis, myocardial infarction
• Sudden death possible (especially with giant aneurysms)

Cardiac Complication	Timing	Frequency/Details
Coronary artery aneurysms	Weeks 2-4	Most important. See above. Leading cause of long-term morbidity/mortality
Myocarditis	Acute phase	Common, usually subclinical. May have tachycardia, gallop, decreased function
Pericarditis/pericardial effusion	Acute phase	Common, usually mild. Large effusions rare
Valvulitis	Acute phase	Usually mild mitral or aortic regurgitation
Arrhythmias	Any phase	Rare but can be life-threatening
Myocardial infarction	Acute or years later	From thrombosis of aneurysm or stenosis. 2-3% of untreated. Can occur decades later

Other Systemic Manifestations

System	Manifestations
GI	Diarrhea, vomiting, abdominal pain, hepatomegaly, hepatitis, gallbladder hydrops (on ultrasound), pancreatitis (rare)
MSK	Arthralgia/arthritis (30-50%), typically small joints of hands/feet, may affect large joints
Neuro	Extreme irritability (hallmark), aseptic meningitis (CSF pleocytosis), rarely encephalopathy, seizures, stroke
Renal	Sterile pyuria (urethritis), mild proteinuria, acute kidney injury (rare)
Respiratory	Rhinorrhea, cough, infiltrates on CXR (rare), pleural effusion

🔬Diagnostic Evaluation

No Specific Diagnostic Test: Kawasaki disease is a clinical diagnosis supported by laboratory findings. High index of suspicion critical, especially for incomplete cases.

Initial Laboratory Workup

Test	Expected Finding	Clinical Significance
CBC with differential	• Leukocytosis (WBC 12,000-40,000) • Anemia (normocytic, normochromic) • Thrombocytosis after day 7 (often >450,000, can be >1 million)	Initial thrombocytosis may be absent in first week. Peaks week 2-3
ESR	Markedly elevated (usually >40 mm/hr, often >100)	Supports diagnosis. May remain elevated for weeks
CRP	Elevated (usually ≥3.0 mg/dL)	Acute phase reactant. Normalizes faster than ESR with treatment
Albumin	Low (≤3.0 g/dL)	Negative acute phase reactant
ALT/AST	Mildly elevated in ~40%	Hepatic involvement
Urinalysis	Sterile pyuria (≥10 WBC/hpf)	From urethritis. No bacteria on culture
BNP or NT-proBNP	May be elevated	Marker of myocardial dysfunction/inflammation

Cardiac Evaluation (ESSENTIAL!) Grade A

ALL suspected Kawasaki disease patients require:
• Baseline echocardiogram
• ECG
• Cardiology consultation

Echocardiography Protocol

Timing:
• Baseline: At diagnosis (before treatment)
• Week 2: Repeat at 2 weeks (or earlier if abnormal baseline or concern for deterioration)
• Week 6-8: Follow-up at 6-8 weeks
• Beyond: Based on findings and risk stratification

What to Assess:
• Coronary artery dimensions (measure proximal RCA, LAD, LCx)
• Z-scores (normalize dimensions for body surface area) - PREFERRED
• Coronary artery aneurysms, dilation, stenosis
• LV function (ejection fraction, fractional shortening)
• Valvular regurgitation
• Pericardial effusion
• Myocarditis indicators (wall motion abnormalities)

ECG Findings

May show: Prolonged PR interval, ST-T changes, low voltage, arrhythmias
Not diagnostic but screens for conduction abnormalities
Q waves = myocardial infarction → EMERGENCY

Differential Diagnosis

Disease	Key Distinguishing Features
Scarlet fever	Sandpaper rash, strawberry tongue, pharyngeal exudate, positive Strep test. Responds quickly to antibiotics
Toxic shock syndrome (Staph/Strep)	Hypotension, multiorgan failure, diffuse erythroderma, desquamation of palms/soles. More acute/severe
Stevens-Johnson syndrome	Target lesions, vesicles/bullae, more severe mucosal involvement, medication history
Viral exanthems (Measles, EBV, Adenovirus)	Specific viral syndrome features, appropriate testing. Usually less prolonged fever
Drug hypersensitivity	Medication history, different timeline, eosinophilia often present
Systemic JIA	Quotidian fever pattern, salmon-pink rash, arthritis prominent, elevated ferritin
Rocky Mountain Spotted Fever	Tick exposure, petechial rash starting on wrists/ankles, more toxic appearance
Leptospirosis	Exposure history, conjunctival suffusion, hepatorenal involvement

Key Point: If uncertain, treat as Kawasaki disease! Risk of missing KD (coronary aneurysms, MI, death) far exceeds risk of IVIG treatment. "When in doubt, give IVIG!"

💊Treatment & Management

TIME IS MYOCARDIUM!
• Treatment within 10 days of fever onset: <5% risk of coronary aneurysms
• Treatment after 10 days: 10-15% risk
• No treatment: 15-25% risk

Goal: Reduce inflammation, prevent coronary artery abnormalities, provide supportive care
Setting: Hospitalize all patients for initial treatment and monitoring

🥇 First-Line Therapy Grade A

IVIG (Intravenous Immunoglobulin)

Dose: 2 g/kg as single infusion over 10-12 hours
Timing: As soon as diagnosis made, ideally within 10 days of fever onset
Efficacy: Reduces coronary aneurysm risk from 25% to <5%
Mechanism: Immunomodulatory (multiple mechanisms)

Adverse Effects (Monitor During Infusion):
• Infusion reactions (fever, chills, headache) - slow/stop infusion temporarily
• Allergic reactions - rare
• Volume overload - especially in heart failure
• Aseptic meningitis - rare, self-limited
• Hemolytic anemia - rare
• Thrombosis - rare

Contraindications: IgA deficiency (relative - risk of anaphylaxis)

Aspirin

High-Dose (Anti-inflammatory Phase):
Dose: 80-100 mg/kg/day divided QID
Duration: Until afebrile for 48-72 hours
Purpose: Anti-inflammatory effect

Low-Dose (Antiplatelet Phase):
Dose: 3-5 mg/kg/day once daily (usually 81 mg/day for children)
Duration:
• No coronary abnormalities: 6-8 weeks (until echo normal and ESR/CRP normal)
• Coronary abnormalities: Indefinitely (lifelong if giant aneurysms)
Purpose: Antiplatelet/antithrombotic

Note: Risk of Reye syndrome during acute illness with aspirin, but benefits outweigh risks. Avoid live vaccines (varicella, MMR) for 11 months after IVIG

Response Assessment:
• Expect defervescence within 24-36 hours of IVIG
• Persistent or recrudescent fever ≥36 hours after IVIG = IVIG-resistant KD
• 10-20% of patients are IVIG-resistant (higher risk for coronary abnormalities!)

🔄 IVIG-Resistant Kawasaki Disease

Definition: Persistent or recrudescent fever ≥36 hours after completing initial IVIG infusion
Risk: 10-20% of patients. Higher risk for coronary aneurysms
Approach: Consult cardiology/rheumatology. Multiple options available.

Second-Line Therapies

Option 1: Second IVIG Infusion (Most Common)
Dose: 2 g/kg × 1
Evidence: Standard approach, effective in ~50%
Can repeat if needed

Option 2: Methylprednisolone (Corticosteroids)
IV Pulse: 30 mg/kg/day × 1-3 days (max 1 g/day)
OR
IV/PO: 2 mg/kg/day divided BID, then taper

Evidence: Effective for IVIG-resistant. Controversial as initial therapy (may use in high-risk patients)

Option 3: Infliximab (Anti-TNF-α)
Dose: 5 mg/kg IV × 1 (over 2 hours)
Evidence: Increasing use. Effective for IVIG-resistant KD. May use as initial therapy in high-risk patients
Advantage: Single dose, rapid action

Option 4: Other Biologics (Refractory Cases)
• Anakinra (IL-1 receptor antagonist): 2 mg/kg/day SC
• Tocilizumab (IL-6 inhibitor): Case reports
• Abciximab (antiplatelet): For thrombotic complications

Limited data, reserve for refractory cases. Expert consultation recommended

💊 Adjunctive Therapies (Based on Complications)

Indication	Treatment
Coronary aneurysms (small-medium)	Low-dose aspirin long-term. Consider adding clopidogrel if high risk
Giant coronary aneurysms (≥8mm)	Low-dose aspirin + warfarin (INR 2-3) OR low molecular weight heparin. Lifelong anticoagulation. Cardiology follow-up
Coronary thrombosis	Thrombolytics (tPA), anticoagulation, possible PCI. EMERGENCY - pediatric cardiology/interventional cardiology
Myocardial infarction	Standard MI management + cardiology. Consider catheterization, ECMO if severe
Heart failure	Diuretics, ACE inhibitors, inotropes as needed. Cardiology management

📋 Long-Term Management & Follow-Up

Risk Stratification (AHA 2017)

Risk Level	Coronary Status	Follow-Up
Level 1 (Lowest)	No coronary abnormalities at any stage	• Low-dose aspirin 6-8 weeks • Echo at 2 wks, 6-8 wks • Cardiology at 6-8 wks, then discharge • No activity restrictions • Cardiovascular risk assessment at 5-year intervals in adulthood
Level 2	Transient coronary dilation, resolved	• Low-dose aspirin 3-6 months • Annual cardiology follow-up × 5 years • Echo annually × 5 years • No competitive sports for 6 months • Long-term cardiovascular surveillance
Level 3	Small-medium coronary aneurysms	• Low-dose aspirin indefinitely • Consider adding clopidogrel/warfarin • Cardiology every 6-12 months • Echo annually, stress test periodically • Activity restrictions individualized • Lifelong surveillance
Level 4	Giant coronary aneurysms (≥8mm) or coronary stenosis	• Aspirin + warfarin/LMWH lifelong • ± β-blocker • Cardiology every 6 months • Echo every 6-12 months • Annual stress test, consider coronary angiography • Significant activity restrictions • Lifelong intensive surveillance
Level 5 (Highest)	Coronary obstruction/MI	• Intensive anticoagulation • ± β-blocker, ACE-I, statins • Frequent cardiology follow-up • Catheterization/revascularization as needed • Severe activity restrictions • Consider cardiac transplantation if advanced disease

🏫 Return to School/Activities

Children with no coronary abnormalities: Return to full activity after inflammatory markers normalize (typically 6-8 weeks)
Children with coronary abnormalities: Individualized based on severity (cardiology guidance)
School re-entry after hospitalization discharge if feeling well

💉 Vaccination Considerations

Live vaccines (MMR, varicella): Delay 11 months after IVIG (passive antibodies interfere)
Inactivated vaccines: Can give on schedule
Influenza vaccine: Annual, especially if on aspirin (Reye syndrome risk if influenza infection)
If due for vaccines, delay IVIG if possible, or re-vaccinate after 11 months

References: McCrindle BW, et al. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: AHA Scientific Statement. Circulation. 2017;135(17):e927-e999. | AAP. Red Book. 2021-2024. | Newburger JW, et al. Kawasaki Disease. JACC. 2016;67(14):1738-1749.

🌡️ Exanthematic Diseases

🔴 Measles (Rubeola)

🌸 Rubella (German Measles)

👋 Erythema Infectiosum

🌹 Roseola Infantum

💧 Varicella (Chickenpox)

🦠 Scarlet Fever

✋ Hand-Foot-Mouth Disease

❤️ Kawasaki Disease

🔴 Measles (Rubeola) - First Disease

📋Disease Overview

Key Characteristics

Classic Clinical Triad

🩺Clinical Presentation

Three-Stage Disease Course

Modified Measles (Vaccinated/Partially Immune)

🔬Diagnosis

Clinical Diagnosis Criteria (WHO)

Laboratory Confirmation Grade A

Recommended Laboratory Workup

Differential Diagnosis

💊Treatment & Management

🏠 Supportive Care Grade A

💉 Vitamin A Supplementation Grade A

Indications for Vitamin A (AAP):

🏥 Hospitalization Criteria

🦠 Complications (Occur in ~30% of cases)

Common Complications

Severe/Life-Threatening Complications

🛡️ Post-Exposure Prophylaxis Grade A

Option 1: MMR Vaccine (Preferred for eligible)

Option 2: Immunoglobulin (IG)

No Prophylaxis Needed:

🏥 Isolation Precautions

🌸 Rubella (German Measles) - Third Disease

📋Disease Overview

Key Characteristics

Clinical Features

Classic Triad

Prodrome (1-5 days before rash)

Rash Characteristics

⚠️ Complications (Rare in Children)

🔬Diagnosis

Laboratory Tests

Differential Diagnosis

💊Management

Treatment (Supportive Only)

🤰 Pregnancy Exposure Management

Step 1: Determine Immune Status

Step 2: If Non-Immune or Unknown

Step 3: If Infection Confirmed

Prevention

🛡️ Prevention - MMR Vaccine Grade A

👋 Erythema Infectiosum (Fifth Disease)

📋Disease Overview

Key Characteristics

Classic Clinical Presentation

⚠️ Complications & High-Risk Groups

1. Aplastic Crisis (Patients with Hemolytic Anemias)

2. Pregnancy Complications

3. Immunocompromised Patients

4. Arthropathy

🔬Diagnosis

Laboratory Testing

Differential Diagnosis

💊Management

Treatment (Supportive for Uncomplicated Cases)

Special Situations - Treatment

Aplastic Crisis

Chronic Infection (Immunocompromised)

Hydrops Fetalis

🛡️ Prevention

🌹 Roseola Infantum (Sixth Disease)

📋Disease Overview

Key Characteristics

Clinical Presentation

⚠️ Complications

🔬Diagnosis

Diagnostic Approach

Laboratory Testing (When Needed)