A Case of Finger Osteonecrosis in Dermatomyositis Treated by Amputation of the Proximal Phalanx

Connective tissue diseases and vasculitis can cause Raynaud's phenomenon, which reduces the blood flow to the skin. Skin ulcers are a common symptom in patients with scleroderma, but they are less common in cases with dermatomyositis. A 66-year-old woman was diagnosed with dermatomyositis and tested positive for the anti-melanoma differentiation-associated gene 5 antibody. During the treatment for dermatomyositis, the patient developed acute interstitial pneumonia and a skin ulcer on the tip of her left index finger. A skin biopsy revealed vasculopathy, suggesting that the skin ulcer was a complication of dermatomyositis. The patient was treated with pulse steroid therapy, immunosuppressive drugs, and plasma exchange therapy, which improved her respiratory function. However, the skin ulcer progressively worsened until it involved the middle phalanx and eventually led to osteonecrosis. Pain management was difficult because of osteomyelitis of the middle phalanx and the destruction of the distal interphalangeal joint. As gangrene did not progress, the proximal phalanx was amputated. One year and ten months after the surgery, the wound was closed, the ulcer did not reoccur, and the patient was pain-free. Patients with dermatomyositis who are positive for anti-melanoma differentiation-associated gene 5 antibodies rarely present with skin ulcers or osteonecrosis. In some cases, however, amputation is considered to be an acceptable treatment option.