How should I manage a 35-year-old woman with two days of fever (102 °F), a one‑day vesicular rash, and a known close contact exposure to varicella (chickenpox)?

Management of Suspected Adult Varicella

This is a case of primary varicella (chickenpox) in an adult, and you should immediately initiate oral acyclovir 800 mg five times daily for 7-10 days, as adults are at significantly higher risk for severe complications including varicella pneumonia compared to children 1, 2.

Immediate Clinical Assessment

Confirm the Diagnosis

• The presentation is classic: fever followed by vesicular rash with known varicella exposure
• Look specifically for:
  • Vesicles in different stages (papules, vesicles, crusted lesions) appearing in crops
  • Distribution starting on face/trunk then spreading to extremities
  • Lesions on scalp and mucous membranes (distinguishes from smallpox)
• If diagnosis is uncertain, obtain VZV PCR from vesicle fluid or direct fluorescent antibody testing

Risk Stratification for Complications

Adults have 25 times higher mortality than children from varicella 3. Assess for:

• Respiratory symptoms (cough, dyspnea, chest pain) - varicella pneumonia develops in 10-20% of adult cases and can progress rapidly 1
• Immunocompromised status (HIV, steroids >20mg/day prednisone, chemotherapy)
• Pregnancy status (critical - different management pathway)
• Neurologic symptoms (headache, altered mental status, ataxia)

Treatment Algorithm

For Immunocompetent Adults (This Patient)

Start oral acyclovir 800 mg five times daily for 7-10 days immediately - most effective when initiated within 24 hours of rash onset but beneficial up to 72 hours 2, 3. The patient is already at day 1 of rash, so time is critical.

Alternative: Valacyclovir 1000 mg three times daily (better bioavailability, easier dosing) 4

Supportive Care

• Antihistamines for pruritus
• Acetaminophen for fever (avoid NSAIDs - theoretical risk of necrotizing fasciitis)
• Keep nails trimmed to prevent secondary bacterial infection
• Calamine lotion for symptomatic relief

Red Flags Requiring Hospitalization and IV Acyclovir

• Any respiratory symptoms (tachypnea, hypoxia, cough)
• Hemorrhagic lesions
• Altered mental status or severe headache
• Immunocompromised state
• Inability to tolerate oral medications

If pneumonia develops: Admit immediately for IV acyclovir 10-15 mg/kg every 8 hours, as varicella pneumonia can rapidly progress to respiratory failure requiring ICU care 1.

Infection Control and Exposure Management

Isolation

• Patient is highly contagious from 1-2 days before rash until all lesions are crusted (typically 5-7 days)
• Airborne and contact precautions
• Avoid contact with pregnant women, immunocompromised individuals, and infants

Assess Patient's Immunity Status

The guideline framework requires determining if this patient truly lacked immunity 5:

• Obtain varicella history - did she have chickenpox as a child?
• Check vaccination records
• If uncertain, this is likely primary infection given the clinical presentation

Common Pitfalls to Avoid

1. Delaying antiviral therapy - Don't wait for confirmatory testing if clinical diagnosis is clear. Adults need treatment.

2. Missing varicella pneumonia - Specifically ask about and examine for respiratory symptoms. Pneumonia can develop 3-7 days after rash onset and is the leading cause of death in adults with varicella 1.

3. Misdiagnosing as herpes zoster - Varicella is generalized and bilateral; zoster is dermatomal and unilateral. However, rare concurrent presentations can occur 4.

4. Starting corticosteroids - Never initiate steroids for suspected varicella, as this can lead to disseminated disease 6.

5. Assuming vaccination equals immunity - Breakthrough varicella can occur, though typically milder.

Follow-Up

• Daily phone contact for first 3-5 days to monitor for complications
• Return immediately if: difficulty breathing, chest pain, severe headache, confusion, or hemorrhagic lesions develop
• Expect new lesions for 3-5 days, complete crusting by 7-10 days
• Patient remains contagious until all lesions crusted

The key to reducing morbidity and mortality in adult varicella is early antiviral initiation and vigilant monitoring for pneumonia, which remains the most serious complication in immunocompetent adults.