Pathophysiology & Risk Factors

Two pediatric communicable diseases with very different transmission. Varicella (chickenpox) spreads by airborne aerosol AND direct vesicle contact, requiring airborne plus contact precautions. Pertussis (whooping cough) spreads by droplet only. Telling them apart drives the correct isolation tier and treatment.

Varicella vs Pertussis

VaricellaPertussis

HallmarkRash in all stages at onceParoxysmal cough with whoop

IsolationAirborne + contactDroplet

Infant dangerSecondary skin infectionApnea instead of whoop

Varicella

Hallmark: Rash in all stages at once
Isolation: Airborne + contact
Infant danger: Secondary skin infection

Pertussis

Hallmark: Paroxysmal cough with whoop
Isolation: Droplet
Infant danger: Apnea instead of whoop

Signs & Symptoms

EarlyProgresses →

Rash begins on trunk

then spreads to face and extremities

Intense pruritus

Catarrhal cold-like symptoms

pertussis: mild URI, most contagious

Late / Severe

Paroxysmal coughing fits

pertussis paroxysmal stage

Inspiratory whoop

older children; infants may not whoop

Post-tussive vomiting

Other findings

Lesions in all stages simultaneously Hallmark

macules, papules, vesicles, crusts together

Interventions & Priorities

Negative-pressure room for varicella

airborne + contact precautions, N95

Droplet precautions for pertussis

Maintain precautions until all lesions crusted

varicella contagious until fully crusted

Treatments & Medications

Macrolide antibiotic

azithromycin or erythromycin for pertussis

Macrolide post-exposure prophylaxis for contacts

regardless of vaccination status

Acetaminophen for fever

preferred antipyretic in varicella

Calamine lotion for itching

Acyclovir

reduces varicella severity; does not affect contagiousness

Patient Teaching

Trim fingernails short

prevents scratching, skin breaks, secondary infection

Return to school only after all lesions crusted

not when new lesions merely stop

Avoid topical antibiotics on intact vesicles

reserve for confirmed infected lesions

DTaP not given before 6 weeks of age

no protection for exposed newborn

Complications

Secondary bacterial skin infection Hallmark

honey-crusted lesions; most common varicella complication, often Group A Strep

Varicella pneumonia

Varicella encephalitis

Report Nowescalate immediately

Apnea in infant with pertussis

under 6 months present with apnea, not whoop

Perioral cyanosis after coughing

life-threatening in young infants

Aspirin in varicella

contraindicated; Reye syndrome risk

Honey-crusted erythematous lesions

secondary bacterial superinfection

Clinical Pearl

Varicella: all stages at once, airborne room, never aspirin. Pertussis: the whoop gets attention, but the cold stage spreads the disease - and infants go apneic instead of whooping.

Varicella & Pertussis