P21 Facial papules in an immunocompromised patient

Abstract

Abstract A 29-year-old man presented with a 6-week history of clustered facial papules. Of note, he had a diagnosis of HIV 5 months previously and was on maintenance antiretroviral treatment. His initial CD4 count was 5, which increased to 38, and his viral load was now no longer detectable. He had also been treated for cytomegalovirus reactivation, pneumocystis pneumonia and suspected mycobacterium infection for the previous 3 months. He had ongoing symptoms of malaise, fevers, weight loss and nausea, along with abnormal liver function tests and a raised C-reactive protein. A bone marrow trephine showed noncaseating discrete small granulomas; Grocott and periodic acid–Schiff (PAS) stains were negative. Prior to his dermatology review, the papules were initially perioral and he had been treated with empiric valaciclovir for suspected herpes simplex virus (HSV) but with no resolution. Testing for HSV DNA and syphilis was negative. On examination, there were clusters of small nontender, well-circumscribed papules (some umbilicated), distributed on the forehead, cheeks, and cutaneous and mucosal lips. A diagnostic punch biopsy was taken of one of the characteristic papules. Histological examination demonstrated a dense dermal infiltrate of histiocytes with focal non-necrotizing granuloma formation. Interspersed neutrophilic microabscesses and occasional eosinophils were present. PAS stain for fungi confirmed the presence of numerous thick-walled spherules, many with a single distinct nucleus, with some showing binucleation, consistent with fungal organisms located within the histiocytes in the dermis. Differential diagnosis included histoplasmosis, cryptococcosis, blastomycosis and coccidiomycosis. He was commenced on intravenous liposomal amphotericin B for disseminated endemic mycosis while awaiting definitive diagnosis. Formal identification by panfungal polymerase chain reaction of skin tissue was positive for Histoplasma capsulatum and itraconazole was added. The diagnosis was consistent with disseminated histoplasmosis with cutaneous involvement. The lesions resolved completely over 4 weeks, with some residual hyperpigmentation remaining. Histoplasma capsulatum is a dimorphic fungus found in soil and the droppings of bats and birds. Infection is through spore inhalation, with most patients being asymptomatic. It is more prevalent in temperate and tropical climates. Disseminated histoplasmosis occurs mostly in immunocompromised individuals and can be fatal if left untreated. Although endemic to specific world regions, disseminated histoplasmosis should be considered in immunocompromised patients presenting with atypical cutaneous findings, even in regions of low prevalence.