Dermoscopic features of some scalp disorders

Background The diagnosis and management of hair and scalp disorders presents a unique challenge for the physician. Dermoscopy has been utilized in recent years for the diagnosis of various hair and scalp diseases. Objective To evaluate the use of dermoscopy as a diagnostic tool for common hair disorders and its application in everyday practice. Patients and methods The present study included 127 patients with various hair disorders. Their clinical diagnoses were alopecia areata (AA) in 43 patients, androgenetic alopecia in 35 patients, scalp psoriasis in 21 patients, scalp seborrheic dermatitis in 14 patients, tinea capitis in 11 patients, and discoid lupus erythematosus (DLE) in three female patients. Dermatoscopic examination was performed using a polarized-light handheld dermatoscope. Results In AA clustered vellus hairs, black dots, tapered hairs, coudability hairs, and yellow dots were specific features, whereas in androgenic alopecia, greater than 20% hair diameter diversity and peripilar sign were specific. Interfollicular red dots were specific for psoriasis, whereas follicular red dots were specific for DLE. Arborizing blood vessels were features of DLE, seborrheic dermatitis, and psoriasis, in descending frequency. Comma-like hair was a specific feature of tinea capitis. White and brown dyscromia, reduction of follicular ostia, and blue dots were specific features for DLE. Conclusion Dermoscopy may be useful in the differential diagnosis of AA, androgenetic alopecia, and tinea capitis. Specification of vascular patterns by dermoscopy can be valuable for the clinical differentiation of scalp psoriasis and seborrheic dermatitis. Dermoscopy may be useful in the evaluation of disease activity of DLE and AA by detecting features of activity and remission.