Etanercept-Induced Henoch-Schonlein Purpura in a Patient With Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily affects the axial skeleton. Extra-articular manifestations are less common relative to other rheumatic diseases, and vasculitic complications typically involve the ascending aorta and aortic valve. The use of tumor necrosis factor inhibitors is efficacious in the treatment of patients with AS. Since their routine use, however, tumor necrosis factor inhibitors have been associated with the development of drug-induced complications including the induction of lupus and both cutaneous and systemic vasculitis. In this report, we describe a patient with severe longstanding AS, who developed Henoch-Schonlein purpura after commencing therapy with etanercept. Tumor necrosis factor inhibitor-induced Henoch-Schonlein purpura has been very rarely reported and has been mostly recognized in patients with rheumatoid arthritis.