Abstract
Cutaneous vasculitis (CV) is a condition with cutaneous manifestations and possible systemic involvement. The causative factors or associated diseases are usually drugs, infection, collagen vascular disease, or malignancy. Syphilis as a cause of cutaneous vasculitis is rare. We report the case of a large cutaneous ulcer and small‐vessel vasculitis associated with syphilis infection. We suggest that in apparently idiopathic CV or a chronic ulcer refractory to treatment, screening should be performed to detect any underlying infection such as syphilis. It is important to have a rapid and accurate diagnosis because the lesions are very contagious, but may be rapidly and completely cured by early administration of antibiotic treatment.