LAUSR

Autoantibodies to melanoma differentiation‐associated protein 5 (MDA5) are associated with a subset of patients with dermatomyositis (DM) who have rapidly progressive interstitial lung disease (RP‐ILD) with poor prognosis. Intensive immunosuppressive therapy is initiated before irreversible lung damage can occur; however, there are few lines of evidence for the treatment of RP‐ILD. Here, we report three cases of anti‐MDA5 antibody‐associated DM with RP‐ILD in which the patients were treated with combined‐modality therapy, including high‐dose prednisolone, tacrolimus, intravenous cyclophosphamide and intravenous immunoglobulin (IVIG). In all three cases, serum ferritin levels, which are known to represent the disease activity of RP‐ILD, were decreased after IVIG administration. IVIG might contribute to the control of the disease activity of anti‐MDA5 antibody‐positive DM. Moreover, palmar violaceous macules/papules around the interphalangeal joints, which was observed in all three cases in the incipient stage, might be a useful sign in suggesting a diagnosis of anti‐MDA5 antibody‐associated DM.