Alopecia Areata - Diagnosis

Diagnosis

Alopecia areata is usually diagnosed based on clinical features.

Trichoscopy may aid differential diagnosis. In alopecia areata trichoscopy shows regularly distributed "yellow dots" (hyperkeratotic plugs), micro-exclamation mark hairs, and "black dots" (destroyed hairs in the hair follicle opening).

A biopsy is rarely needed in alopecia areata. Histologic findings include peribulbar lymphocytic infiltrate ("swarm of bees"). Occasionally, in inactive alopecia areata, no inflammatory infiltrates are found. Other helpful findings include pigment incontinence in the hair bulb and follicular stelae and a shift in the anagen-to-telogen ratio towards telogen.