Erythematous rash and proximal muscle weakness in a 59-year-old woman: Delayed diagnosis of dermatomyositis in a patient with skin of color.

Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by proximal muscle weakness and pathognomonic cutaneous manifestations. Recognition in patients with skin of color can be delayed due to atypical presentation of classic rashes. A 59-year-old woman with type 2 diabetes mellitus and hypertension presented with progressive weakness, dyspnea, palpitations, edema, and significant unintentional weight loss. Initial evaluation revealed elevated transaminases and troponin, and she was managed for suspected autoimmune myocarditis. On readmission, she had hyperpigmented and violaceous patches on the chest, lower abdomen, and thighs and erythema with tenderness of the distal fingers and cuticles. Serologic testing was positive for ANA and anti-Mi-2 antibody, confirming dermatomyositis. She was treated with intravenous immunoglobulin and systemic corticosteroids, resulting in clinical improvement and discharge to a rehabilitation facility. Dermatomyositis has an estimated incidence of 1-6 per 100,000 in the United States, with increased prevalence among women and patients of African ancestry. Recognition of DM in skin of color is often delayed, as erythematous eruptions may appear as hyperpigmented or violaceous lesions, leading to diagnostic uncertainty. This delay can contribute to significant morbidity and recurrent hospitalizations. Increasing diversity in dermatology education and clinical resources is essential to improve recognition and outcomes.