BI28 A rare case of cutaneous leishmaniasis associated with guselkumab

Abstract Leishmaniasis is a parasitic infection caused by a protozoan of the genus Leishmania, transmitted through infected female sandflies. Known risk factors for leishmaniasis include living in or travelling to endemic regions, particularly tropical areas such as the Mediterranean, and poor socioeconomic status and immunosuppression (Oryan A, Akbari M. Worldwide risk factors in leishmaniasis. Asian Pac J Trop Med 2016; 9: 925–32). We present the case of a 68-year-old White man on guselkumab for plaque psoriasis, who presented with persistent erythematous plaques that histologically were confirmed as cutaneous leishmaniasis. The patient was managing his psoriasis well with guselkumab, an anti-interleukin-23 monoclonal antibody. Five years into his treatment with guselkumab, in clinic, two erythematous plaques appeared on his left arm. They were pruritic but nontender. He reported frequent travel to Spain, Cape Verde and Brazil. These lesions were initially treated as psoriasis, but the plaques persisted despite the use of additional topical therapy. A biopsy was carried out, given the plaque’s persistence and patient’s past medical history of squamous cell carcinoma. Histopathology results showed no evidence of malignancy, but there were sheets of histiocytes in the dermis forming a florid non-necrotizing granulomatous infiltrate. The histiocytes contained abundant microorganisms within their cytoplasm. The appearances were highly suggestive of cutaneous leishmaniasis. The patient is currently cared for jointly with the infectious diseases team. The patient is progressing well and has commenced miltefosine, which has reduced the size of the lesions on his arms. The patient continues to do well on guselkumab for his psoriasis. There are cases of cutaneous leishmaniasis reported in patients on anti-tumour necrosis factor therapy (Valdés Delgado T, Rodríguez Delgado C, Pérez-Pérez M. Mucocutaneous leishmaniasis associated with anti-TNF therapy: a case report. Inflamm Bowel Dis 2022; 28: e3–4). However, to the best of our knowledge, we are the first to report a case of cutaneous leishmaniasis in a patient treated with guselkumab. Our case highlights the importance of early diagnosis and prompt management of cutaneous leishmaniasis to prevent disease progression, particularly in immunocompromised patients. Travel advice to endemic regions should also be considered in patients receiving biologics such as interleukin-23 inhibitors.