A Case of Native Joint Septic Arthritis Due to Histoplasma Capsulatum in a Patient on Adalimumab

Disseminated histoplasmosis is primarily a disease of the immunosuppressed, with clinically significant symptoms most commonly observed in the lungs, intra-abdominal organs, or central nervous system. We present a case of native joint septic arthritis due to Histoplasma capsulatum in an 88-year-old male on adalimumab for psoriasis with no other etiologies for immunosuppression. The patient presented with four weeks of right knee pain without inciting trauma. Synovial fungal cultures grew Histoplasma capsulatum. He underwent incision and drainage with anterior compartment synovectomy along with six months of oral itraconazole. Ultimately, the patient's infection resolved. Repeat cultures were negative, and he returned to his baseline physical activity. While recombinant monoclonal antibodies such as adalimumab have been revolutionary in the treatment of autoimmune diseases, this case highlights how infections may have atypical presentations and the importance of close infection surveillance for those on these medications.