Hydroxychloroquine sulfate is a commonly used medication for patients with dermatomyositis and has been associated with a uniquely elevated risk of adverse cutaneous reactions in this population. No studies to date have examined whether certain subsets of patients with dermatomyositis are at increased risk of experiencing a hydroxychloroquine-associated skin eruption.

To identify disease features that increase the risk of hydroxychloroquine-associated skin eruption in adults with dermatomyositis.

A retrospective cohort study was conducted in the outpatient dermatology clinic at a tertiary academic referral center. All adults with dermatomyositis (age >18 years) who started receiving hydroxychloroquine between July 1, 1990, and September 13, 2016, were eligible for the analysis. Patients were considered to have a hydroxychloroquine-associated skin eruption if a skin eruption had developed within their first 4 weeks of treatment and resolved with discontinuation of hydroxychloroquine therapy.

One or more doses of hydroxychloroquine.

The associations between autoantibodies (against transcription intermediary factor 1γ [TIF-1γ], nucleosome-remodeling deacetylase complex [Mi-2], nuclear matrix protein [NXP-2], small ubiquitinlike modifier 1 activating enzyme [SAE-1/2], melanoma differentiation-associated gene 5 [MDA-5], histidyl-transfer RNA synthetase [Jo-1], Ku, and signal recognition particles) and cutaneous adverse reactions to hydroxychloroquine in patients with dermatomyositis.

A total of 111 patients met the inclusion criteria, and 23 (20.7%) developed a hydroxychloroquine-associated skin eruption (20 [87.0%] were women with a mean [SD] age of 49 [14] years at diagnosis). Skin eruptions were approximately 3 times more common in patients with anti-SAE-1/2 autoantibodies (7 of 14 [50.0%]) compared with those without the autoantibody (16 of 97 [16.5%]). In contrast, none of 15 patients with anti-MDA-5 autoantibodies had a skin eruption vs 23 of 96 (24.0%) of those without the autoantibody. In exact logistic regressions adjusted for age, race/ethnicity, sex, amyopathic status, anti-Ro52 status, and dermatomyositis-associated cancer, the presence of anti-SAE-1/2 autoantibodies was significantly associated with a hydroxychloroquine-associated skin eruption (odds ratio [OR], 8.43; 95% CI, 1.98-49.19; P = .003) and presence of anti-MDA-5 autoantibodies was significantly negatively associated with a hydroxychloroquine-associated skin eruption (OR, 0.06; 95% CI, 0.0004-0.52; P = .006). No other autoantibodies were significantly positively or negatively associated with a hydroxychloroquine-associated skin eruption.

Adverse skin reactions to hydroxychloroquine are relatively common in a US cohort of patients with dermatomyositis. Our data suggest that pathophysiologic differences exist between autoantibody subsets in dermatomyositis.