What is the typical distribution of chickenpox lesions in an immunocompromised patient?

Chickenpox Lesion Distribution in Immunocompromised Patients

Chickenpox lesions in immunocompromised patients follow the same centripetal (trunk-predominant) distribution as in immunocompetent hosts, but with more prolonged eruption (7-14 days versus 4-6 days), slower healing, greater lesion density, and higher risk of disseminated visceral involvement. 1, 2, 3

Distribution Pattern

• Lesions maintain the characteristic centripetal distribution with predominance on the trunk and head rather than extremities, distinguishing chickenpox from smallpox or measles which show centrifugal patterns 1, 4

• Lesions can appear anywhere on the body including palms, soles, and mucosal surfaces (mouth, conjunctivae), with no anatomic site spared 1

• The trunk-centered pattern persists regardless of immune status, though immunocompromised patients develop more extensive and confluent lesions 2, 4

Key Differences in Immunocompromised Hosts

Temporal Evolution

• New lesions continue erupting for 7-14 days in immunocompromised patients compared to 4-6 days in healthy hosts 1, 2, 4

• Healing occurs significantly more slowly, with some patients developing chronic ulcerations and persistent viral replication 1, 3

• Lesions may continue forming beyond the typical timeframe without effective antiviral therapy 1, 2

Disease Severity Markers

• 28% incidence of pneumonitis and 7% mortality rate in untreated immunocompromised children with varicella 3

• 8% risk of visceral dissemination (liver, lungs, CNS) in immunocompromised patients with herpes zoster, compared to rare occurrence in immunocompetent hosts 3

• Greater lesion density and coalescence, potentially forming bullae before scabbing 1, 4

Critical Clinical Pitfalls

• Do not rely on distribution pattern alone to distinguish severity - immunocompromised patients maintain centripetal distribution but require immediate IV acyclovir regardless 2, 3

• Do not wait for dissemination before treating - initiate IV acyclovir 10 mg/kg every 8 hours immediately upon diagnosis in any immunocompromised patient 2, 5

• Do not stop antiviral therapy at 7 days if new lesions are still forming - continue treatment until complete crusting of all lesions occurs 5

• Recognize atypical presentations - some immunocompromised patients present with nonspecific lesions lacking the classic vesicular appearance initially 1, 6

Management Algorithm for Immunocompromised Patients

1. Immediate IV acyclovir 10 mg/kg every 8 hours upon diagnosis, regardless of lesion distribution or density 2, 5

2. Implement strict contact and airborne precautions - immunocompromised patients shed virus longer (mean 7.0 days versus 5.3 days) 3

3. Monitor for visceral complications: pneumonitis, hepatitis, encephalitis - these occur in up to 28% of untreated immunocompromised patients 3

4. Continue treatment minimum 7-10 days and until all lesions have completely scabbed - do not use fixed duration 2, 5

5. Consider secondary bacterial/fungal superinfection - chronic ulcerations are common without adequate treatment 1