Henoch-Schönlein purpura induced by sitagliptin: A case report

Dipeptidyl peptidase-4 inhibitors are oral antihyperglycemic medications often used as adjuncts to other antidiabetic agents to treat type 2 diabetes mellitus. Henoch-Schönlein purpura, also known as ImmunoglobulinA (IgA) vasculitis, is a form of IgA-mediated leukocytoclastic vasculitis, which is rarely reported in adults. Herein, we report the case of a 52-year-old male with type 2 diabetes mellitus who presented with petechiae, ecchymoses, and palpable purpura below the knees bilaterally after starting sitagliptin, a dipeptidyl peptidase-4 inhibitor. A punch biopsy for direct immunofluorescence showed granular Immunoglobulin A, M, and complement 3 in vessel walls, suggestive of Henoch-Schönlein purpura. Sitagliptin was discontinued, and the patient was treated with celecoxib, colchicine, and cefadroxil for wound infection. Three months after initial presentation, brown hyperpigmentation was appreciated, suggestive of post-inflammatory changes and resolution of the lesions. However, urinalysis revealed new 0.3 g/L protein. Overall, this case highlights a new potential association of dipeptidyl peptidase-4 inhibitors with Henoch-Schönlein purpura, which may have systemic consequences.