ABSTRACT
Scalp biopsy is indicated when the diameter of the hair is reduced or when there is doubt about the presence of an inflammatory alopecia. However, a more gradual onset may reflect short anagen phase syndrome and should rule out other conditions such as alopecia areata, androgenic alopecia, and diffuse scarring alopecia. Chronic diffuse alopecia can derive from persistence of acute alopecia, or have a general endocrine or metabolic cause. The shedding results in a diffuse loss with a more prominent central, frontal, and subauricular scalp loss. The hair cycle begins with the anagen growth phase of the hair follicle. Telogen effluvium, or excessive loss of normal hair, reflects a disturbance of the hair cycle. The diagnosis of telogen effluvium is based on the clinical presentation and the confirmation of excess telogen hair loss. A digital phototrichogram can be essential to assess changes in hair density. If there are numerous dystrophic anagen hairs, the diagnosis is an anagen effluvium.
