A Curious Case of Medium-Vessel Vasculitis.

Vasculitis, or the inflammation of vessels due to primary or secondary causes, may arise from numerous etiologies, often leading to diagnostic uncertainty. Delayed treatment due to diagnostic or etiologic uncertainty presents a significant clinical risk, with consequences including organ failure and mortality. We describe a case of a 58-year-old male with a history including ankylosing spondylitis who presented with painful ulcers involving the bilateral lower extremities following a trip to the southern Texas border. Histopathology revealed medium-vessel vasculitis; however, the search for a likely etiology in the setting of a unique combination of potential vasculitis precipitants, including glochid inoculation, a spider bite, prior IL-17 inhibitor use, and inflammatory bowel disease, contributed to treatment delay and disease progression. Although the patient was ultimately successfully treated with systemic corticosteroids, this case highlights the importance of initiating prompt therapy once vasculitis is recognized to prevent disease progression, even if lacking an identified etiology.