Drug-induced Leukocytoclastic Vasculitis Secondary to Trimethoprim/Sulfamethoxazole: A Case Report

Leukocytoclastic vasculitis (LCV) is a small vessel vasculitis typically affecting dermal capillaries and venules. The condition is often idiopathic but can be associated with infections, neoplasms, autoimmune disorders, and certain drugs.

A 91-year-old female with past medical history of Alzheimer dementia and hypertension, being treated for lower extremity cellulitis, presented to the emergency department for an allergic reaction. Trimethoprim/sulfamethoxazole (TMP/SMX) had been initiated six days earlier. The patient was noted to have normal vital signs. Palpable purpura was discovered on the lower back, buttocks, lower extremities, ankles, and feet. Laboratory studies were within normal limits. Given the clinical presentation, physical exam findings, and normal eosinophil count, the diagnosis of LCV secondary to TMP/SMX was made.

Most cases of LCV are limited to cutaneous symptoms and self-resolve with supportive care.