Abstract

Dermatomyositis is an autoimmune idiopathic inflammatory myopathy characterized by progressive, symmetric, proximal muscle weakness, in addition to other systemic and cutaneous features. While it affects all ethnic groups, it has been reported to disproportionately affect Black individuals. Cutaneous presentations of dermatomyositis in the literature are predominantly shown in lighter skin tones. However, clinical presentation can differ significantly in skin of color, and lack of recognition of this condition in darker skin may lead to delayed diagnosis and treatment. A retrospective chart and slide review of 24 patients with dermatomyositis (12 Black and 12 White patients) from 2018 –2023 at a tertiary referral center was conducted to better characterize differences in clinical presentation, histopathology, and outcomes between Black and White patients. Most patients were female (87.5%) and presented at a mean age of 60 years (range 24-84 years). The most common clinical features were Gottron papules (in 41.6% of White patients and 58% of black patients) and heliotrope rash (in 25% of Black patients and 75% of White patients). Dyschromia, including hyper- and hypopigmentation, was seen in 50% of Black patients and was absent in White patients. Histologic features of the biopsies were also reviewed. Interface dermatitis was seen in 75% of Black patients, and 83% of White patients. Dermal mucin, pigment incontinence, and basement membrane thickening were seen in both patient populations, with pigment incontinence more frequently seen in Black patients (83%), and basement membrane thickening more frequently seen in White patients (67%). Additional findings included telangiectasias, epidermal atrophy, and inflammation. To date, this analysis is one of few evaluating cutaneous manifestations and histopathologic features of dermatomyositis in Black patients, a historically understudied population. Recognition of differences in presentation in this subpopulation may help reduce diagnostic delays and poor outcomes in Black patients.