Rash-Negative Dermatomyositis-Spectrum Overlap Myositis With PM/Scl Positivity Presenting With Progressive Pharyngeal Dysphagia.

Dermatomyositis-spectrum inflammatory myopathy may present without characteristic cutaneous findings, and overlap phenotypes can delay recognition when early neuromuscular examination is not yet diagnostic. We describe the case of a patient with rheumatology-diagnosed dermatomyositis without rash and PM/Scl-positive overlap myositis with systemic sclerosis features whose course was marked by interstitial lung disease, progressive weakness, and objectively confirmed pharyngeal dysphagia. A 64-year-old female with interstitial lung disease presented with several weeks of polyarthralgia, severe fatigue, and marked muscle enzyme elevation. Initial examination showed no rash, sclerodactyly, or proximal weakness. Laboratory evaluation demonstrated a creatine kinase level of 12,810 U/L, elevated transaminases, a high-titer antinuclear antibody, positive PM/Scl-100 and PM/Scl-75 antibodies, and a weakly positive Mi-2 antibody. She was diagnosed with dermatomyositis without rash and PM/Scl-positive overlap myositis with systemic sclerosis features and treated with prednisone, mycophenolate mofetil, hydroxychloroquine, and antimicrobial prophylaxis. Intravenous immunoglobulin (IVIG) was recommended but was not initially approved. Her course progressed to severe weakness and dysphagia, ultimately preventing oral medication administration. During hospitalization, a videofluoroscopic swallow evaluation demonstrated aspiration with thin liquids and pharyngeal phase dysphagia. She received IVIG, with subsequent improvement in swallowing and functional status. This report highlights the importance of an overlap-informed approach to inflammatory myopathy when classic cutaneous features are absent. Progressive dysphagia should be treated as a marker of severe disease because it increases the risk of aspiration, contributes to malnutrition, and may prevent the administration of oral immunosuppressive therapy.