BI04 Cutaneous cryptococcosis: a post-transplant cat among the pigeons

Abstract

Abstract Cryptococcosis is an infection caused by the encapsulated yeasts Cryptococcus neoformans and Cryptococcus gattii, which are opportunistic pathogens that mainly affect immunocompromised individuals. Infection is primarily by inhalation and causes pulmonary disease; haematogenous dissemination may affect other organs, particularly the central nervous system, with 10% of disseminated cryptococcosis affecting the skin. Primary cutaneous cryptococcosis due to direct skin inoculation is less common and rarely disseminates. We describe a kidney transplant recipient with disseminated cryptococcosis who presented with skin lesions in the early post-transplant period. As previously observed in a transplant patient with primary cutaneous cryptococcosis under our care, we propose that a history of close contact with urban pigeons was the source of infection. A 48-year-old man who had been transplanted in 2014 presented in May 2022 with a 3-cm-diameter, well-demarcated ulcer on his right shoulder which had been slowly enlarging over 6 weeks in close proximity to his recent COVID-19 vaccination site. Swab was positive for C. neoformans, serology was positive for cryptococcal antigen, chest X-ray showed a 14-mm nodule in the right lung and magnetic resonance imaging of the brain was normal. He was admitted by the transplant team and treated for presumed disseminated cryptococcal infection with intravenous AmBisome® and flucytosine for 2 weeks, and subsequently oral fluconazole. In view of his atypical presentation, we directly questioned him about previous skin disorders and possible sources of infection. It emerged that 6 months earlier, he had noticed multiple lesions on his legs but did not report this as they spontaneously resolved. Mobile phone images showed 0.5–1-cm umbilicated, red–purple nodules consistent with possible primary cutaneous cryptococcosis. We discovered that his balcony was covered in pigeons and their droppings, and he had unsuccessfully asked his local council to provide bird netting. This was the most likely source of his infection, although it is uncertain whether his skin involvement was primary, secondary or both, due to ongoing pigeon exposure. A 54-year-old female patient under our care who had previously presented 3 months post-transplant with extensive noduloulcerative umbilicated lesions confirmed on biopsy to be primary cutaneous cryptococcosis also had close contact with pigeons and their droppings in the immediate post-transplant period. The incidence of cryptococcosis in immunocompromised patients is increasing and cutaneous involvement may be the first manifestation of disseminated disease. The clinical spectrum of skin lesions is highly polymorphic, making diagnosis challenging. However, it should be considered in immunocompromised patients presenting with atypical skin lesions, particularly in the early post-transplant period.