A rare case of malignant syphilis after adalimumab therapy due to Crohn's disease associated with bariatric surgery.

Malignant syphilis (also known lues maligna) is a rare and severe variant of secondary syphilis. It is most commonly seen in patients who are infected with human immunodeficiency virus (HIV), and rarely, it can occur in immunocompetent individuals. The exact mechanism of the development of malignant syphilis is not clear. It could probably be associated with immunosuppression, inappropriate immune response of the host, or virulent strain of Treponema pallidum. Coexistence of immunosuppression and inappropriate immune response may predispose to develop malignant syphilis in HIV-infected patients with immune reconstitution inflammatory syndrome. Herein, we report the first case of malignant syphilis after adalimumab therapy for Crohn's disease due to bariatric surgery and discuss the underlying possible pathogenic mechanisms.