ABSTRACT
A telogen effluvium occurs when abnormally large numbers of anagen hairs from all areas of the scalp enter the telogen phase. This may be caused by some sort of endogenous stress to the follicles, such as a metabolic disturbance, nutritional deficiency, or serious systemic illness. Other cases of telogen effluvium are ‘physiological,’ and not indicative of disease. The many possible causes are listed in Table 9.1. In response to the causative factor, many hairs prematurely enter the catagen phase. This is a committed step for follicles; having entered catagen they must proceed through the telogen phase and shedding before a new anagen hair can regrow.
