Trichoscopy: a new method for diagnosing hair loss.

Videodermoscopy of hair and scalp (trichoscopy) is gaining popularity as a valuable tool in differential diagnosis of hair loss. This method allows viewing of the hair and scalp at X20 to X160 magnifications. Structures which may be visualized by trichoscopy include hair shafts of different types: vellus, terminal, micro-exclamation mark type, monilethrix, Netherton type, and pili annulati hairs. The number of hairs in one pilosebaceous unit may be assessed. It may be distinguished whether hair follicles are normal, empty, fibrotic ("white dots"), filled with hyperkeratotic plugs ("yellow dots") or containing cadaverized hair ("black dots"). Abnormalities of scalp skin color or structure which may be visualized by trichoscopy include honeycomb-type hyperpigmentation, perifollicular discoloration (hyperpigmentation), and scaling.