Clinical and Dermoscopic Features of the Scalp in 31 Patients with Dermatomyositis

Scalp involvement is not directly evaluated in patients with dermatomyositis (DM). Therefore, the exact frequency of scalp dermatomyositis (SDM) and its clinical and trichoscopic characteristics have been poorly described. The aim of this study was to determine the frequency and clinical and dermoscopic features of SDM in patients diagnosed with DM. We performed a descriptive prospective, cross-sectional observational study that included all patients diagnosed with DM at a Mexican academic institute over the course of a year. Twenty-four out of 31 patients with DM had scalp involvement at clinical examination, with a prevalence of 77.4%. SDM was clinically characterized by erythema in all cases, scales in 20 (83.3%) patients, nonscarring alopecia in 21 (87.5%) patients, pruritus in 17 (70.8%) patients, and poikiloderma of the scalp in 16 (51.6%) patients. Twenty-eight patients were evaluated by trichoscopy. The most consistent finding was the presence of enlarged capillaries, found in 20 (71.4%) cases, followed by peripilar casts (57.1%) and tufting and interfollicular scales in 14 (50%) cases. Twenty-two patients also had positive nail fold capillaroscopic features similar to those observed by trichoscopy. The simple size was limited. Scalp involvement and alopecia are common in patients with DM, and trichoscopy shows features similar to those found at capillaroscopy. Trichoscopy is a very important tool for diagnosis of scalp involvement in patients with DM