Dermatomyositis induced by drug therapy: A review of case reports

Background: Drugs have occasionally been implicated in dermatomyositis (DM) onset. Objective: We sought to review case reports of drug-induced DM. Methods: Articles were gathered from MEDLINE and bibliographies of acquired reports. Causality was assessed using World Health Organization criteria. Clinical characteristics, management, and resolution were examined. Results: In 70 reported cases, 50% of patients were female and the median age was 57 years. Hydroxyurea was implicated in 51% of cases. All cases had pathognomonic (76%) or compatible (24%) cutaneous findings. Hydroxyurea cases lacked myositis, but myositis was described in 79.4% of nonhydroxyurea cases. Drug causality was probable (25.7%) or possible (74.3%), but not certain in any case. Most patients had underlying pathology associated with DM (44% had malignancy; 16% had rheumatoid arthritis). Of the sample, 84.3% had improvement of DM after discontinuation of the drug. Limitations: Case reports may emphasize unusual findings. Conclusions: Further work is needed to differentiate drug effects from underlying, predisposing factors.