Factors associated with pruritic papular eruption of human immunodeficiency virus infection in the antiretroviral therapy era

Abstract

Pruritic papular eruption (PPE) of HIV is common in HIV-infected populations living in the tropics. Its aetiology has been attributed to insect bite reactions and it is reported to improve with antiretroviral therapy (ART). Its presence after at least 6months of ART has been proposed as one of several markers of treatment failure. To determine factors associated with PPE in HIV-infected persons receiving ART. A case-control study nested within a 500-person cohort from a teaching hospital in Mbarara, Uganda. Forty-five cases and 90 controls were enrolled. Cases had received ART for ≥15months and had an itchy papular rash for at least 1month with microscopic correlation by skin biopsy. Each case was individually matched with two controls for age, sex and ART duration. Twenty-five of 45 cases (56%) had microscopic findings consistent with PPE. At skin examination and biopsy (study enrolment), a similar proportion of PPE cases and matched controls had plasma HIV RNA<400copiesmL(-1) (96% vs. 85%, P=0·31). The odds of having PPE increased fourfold with every log increase in viral load at ART initiation (P=0·02) but not at study enrolment. CD4 counts at ART initiation and study enrolment, and CD4 gains and CD8(+) T-cell activation measured 6 and 12months after ART commencement were not associated with PPE. Study participants who reported daily insect bites had greater odds of being cases [odds ratio (OR) 8·3, P<0·001] or PPE cases (OR 8·6, P=0·01). Pruritic papular eruption in HIV-infected persons receiving ART for ≥15months was associated with greater HIV viraemia at ART commencement, independent of CD4 count. Skin biopsies are important to distinguish between PPE and other itchy papular eruptions.