Pyoderma Gangrenosum With Severe Ankle Ankylosis Complicated by Rheumatoid Arthritis Successfully Treated Using Anti-tumor Necrosis Factor: A Case Report

Pyoderma gangrenosum (PG) is a rare dermatosis characterised by necrotic ulcers with a predilection mainly for the lower legs. We report a case of a 67-year-old man with PG and severe ankle ankylosis complicated by rheumatoid arthritis (RA) treated with anti-tumor necrosis factor, adalimumab (ADA). He was referred to our hospital because his right ankle showed severe ulcers and blackening. X-rays of the right ankle and foot showed bone and joint destruction with ankylosis. Initially diagnosed with stasis dermatitis, he was treated, but his condition became increasingly worse. A skin biopsy revealed neutrophilic invasion of the skin tissue, and final diagnosis was PG complicated with RA and ankylosing joint. ADA therapy improved the patient's skin condition and reduced the right ankle pain, although severe right ankle ankylosis progressed during the last follow-up. PG should be considered as a differential in patients with RA and refractory skin ulcers.