Propylthiouracil-induced vasculitis

Abstract

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is an autoimmune condition characterized by necrotizing inflammation of small vessels throughout the body. Pharmaceutical agents have been noted as an emerging etiology. This case presents a 41-year-old woman with a longstanding history of Graves' disease who previously failed other interventions and was started on propylthiouracil (PTU) nearly 2 years prior to symptom onset. The patient presented with severely pruritic purpuric lesions on her lower extremities that transformed into large bullae and became extremely painful. A thorough workup revealed only slightly elevated perinuclear ANCA and a mild protein S deficiency. Tissue biopsy was consistent with thrombotic vasculitis. A presumptive clinical diagnosis of PTU-induced vasculitis was made. Because the condition is relatively uncommon, the best course of treatment has not clearly been defined. Though PTU was immediately discontinued, the patient also required corticosteroids and referral for tissue debridement. While some cases have had symptom resolution after cessation of PTU, this case adds to a growing body of evidence for the timely use of corticosteroids in controlling PTU-induced vasculitis.

Keywords: ANCA; Graves’ disease; case report; propylthiouracil; vasculitis.

Figure 1.

Initial skin findings upon presentation to the outside hospital emergency department: (a) posterior bilateral lower extremities and (b) left lateral lower extremity.

Figure 2.

Progression of skin findings 36 hours after arrival to the emergency department: (a) posterior right leg, (b) right lateral leg, (c) right medial leg, and (d) left medial leg.

Figure 3.

Healing process after discontinuation of PTU and initiation of steroids and antibiotics, 28 days after diagnosis of PTU-induced vasculitis: (a) right medial leg, (b) left medial leg, and (c) left lateral leg.