Reactivation of Cutaneous Leishmaniasis in a Rheumatoid Arthritis Patient Undergoing Tocilizumab Treatment.

Cutaneous leishmaniasis is a neglected vector-borne disease caused by Leishmania spp., with viable parasites potentially persisting after clinical cure. Immunosuppressive therapies may favor reactivation of latent infection. The case of a 62-year-old Brazilian woman with a 25-year history of rheumatoid arthritis who developed a painful ulcerative lesion on her right leg 1 month after initiating tocilizumab therapy is reported. Molecular testing confirmed Leishmania (Viannia) braziliensis, consistent with reactivated cutaneous leishmaniasis. Tocilizumab was discontinued, and liposomal amphotericin B was initiated but interrupted because of nephrotoxicity and hepatotoxicity. Despite incomplete treatment, the lesion gradually healed after withdrawal of immunosuppression without requiring additional antiparasitic therapy. Secondary prophylaxis with liposomal amphotericin B was subsequently initiated under close clinical and laboratory monitoring, and no recurrence has been observed during follow-up. This case highlights the importance of screening clinical history for prior leishmaniasis, maintaining vigilance for reactivation in patients from endemic areas, and promptly adjusting immunosuppressive therapy to optimize clinical outcomes.