Further, histopathologic factors common to cutaneous DM lesions, including vacuolar interface dermatitis, perivascular inflammation, increased dermal mucin, and dyskeratotic keratinocytes (3), are also seen in cutaneous lupus erythematosus (CLE) lesions, making DM-associated skin eruptions difficult to distinguish from CLE, especially in the absence of obvious muscle disease or lesional pathognomonic patterns. This evidence concerns the gene MUC5AC and dermatomyositis.