ABSTRACT

Telogen effluvium (TE) describes diffuse loss of telogen hair. Most cases of TE are probably subclinical and epidemiological data on this condition are lacking.

Five types of telogen effluvium can be distinguished depending on the hair cycle abnormality (see Table 7.1):

1. Premature termination of anagen. This is the most common type and is caused by noxae that interrupt the mitotic activity of the hair matrix cells and induce telogen entry. These include systemic diseases, drugs, stress, weight loss, UV exposure, iron deficiency, cigarette smoking and inflammatory scalp disorders. The mechanism by which these different factors cause hair loss is not always clear and involves decreased vascular supply, increased free radical production, cytokine release and toxic effect.

2. Synchronization of the hair cycle due to excessive prolongation of anagen. It develops when the condition that prolongs the anagen duration subsides and synchronized follicles simultaneously enter telogen. This type of TE typically occurs post partum (2-3 months after delivery), after interruption of the contraceptive pill and after discontinuation of topical minoxidil.