BI23 Atopic dermatitis and psoriasis in a patient with HIV: a unique immunological phenomenon

Abstract HIV is often associated with various skin disorders of infectious, inflammatory or neoplastic nature (Coates SJ, Leslie KS. What is new in HIV dermatology? F1000Res 2019; 8: F1000 Faculty Rev-980; Kim J, Kim BE, Leung DYM. Pathophysiology of atopic dermatitis: clinical implications. Allergy Asthma Proc 2019; 40: 84–92). Antiretroviral therapy enhances immunity by improving CD4 counts. We report the case of a 41-year-old man, HIV positive for 1 year, presenting with generalized pruritus and lichenified plaques over his arms consistent with atopic dermatitis. Additionally, erythematous plaques with silvery scales on the trunk, back and thighs were suggestive of plaque and inverse psoriasis. Skin biopsies were obtained for confirmation. Lesions on the arms revealed epidermal irregular acanthosis, spongiosis and hyperkeratosis with no evidence of psoriasiform acanthosis. Lesions on the thighs exhibited psoriasiform acanthosis, diminished granular layers and dilated superficial dermal blood vessels, consistent with psoriasis. Atopic dermatitis, a T helper (Th)2 immune-mediated disorder, and psoriasis, a Th1 phenotype disorder, rarely coexist. However, the impact of HIV on immune regulation may explain this phenomenon. HIV progression results in a Th1/Th2 shift with increased interleukin-4 and interleukin-10 levels and hypergammaglobulinaemia, predisposing patients to Th2 conditions such as atopic dermatitis. Concurrently, activation of CD8+ T cells increases interferon-γ expression, facilitating the manifestation of psoriasis. This unique case highlights the immune dysregulation in HIV leading to the coexistence of two typically distinct immunological skin diseases.