Dermatomyositis induced by anti-tumor necrosis factor in a patient with juvenile idiopathic arthritis.

IMPORTANCE: Biologic therapies, including anti-tumor necrosis factor (TNF) agents, are increasingly used to treat a variety of autoimmune diseases. Paradoxically, these agents have been reported to induce some of the very diseases they were designed to treat, including dermatomyositis (DM). We describe the first case of anti-TNF-associated DM without muscle involvement presenting in an adult patient with a history of arthritis since childhood. This cutaneous eruption recurred after rechallenge with an alternate anti-TNF agent. OBSERVATIONS: A 46-year-old man with juvenile idiopathic arthritis developed a pruritic cutaneous eruption while receiving etanercept. Given concern about a drug-induced eruption, etanercept therapy was discontinued and the cutaneous findings improved. However, after rechallenge with adalimumab, he developed similar findings consistent with the skin manifestations of DM. After discontinuation of all anti-TNF drug therapy and the addition of methotrexate sodium, his eruption improved. CONCLUSIONS AND RELEVANCE: Because the use of these agents is increasing, practitioners should be aware of the possibility of anti-TNF-induced autoimmune disorders, including DM. The case described herein is unique in that anti-TNF-induced autoimmune disease occurred in a patient with existing arthritis since childhood and recurred with rechallenge, adding further evidence to support the existence of anti-TNF-induced DM.