Telogen effluvium. New concepts and review.

Background: Telogen effluvium is the result of a perturbation of the hair cycle that is manifest by increased loss of normal club hairs. Although diverse causes for telogen effluvium have been proposed, this article suggests several diverse mechanisms for the first time.

Observations: Five different functional types of telogen effluvia are proposed based on changes in different phases of the follicular cycle. These are immediate anagen release, delayed anagen release, short anagen syndrome, immediate telogen release, and delayed telogen release. Diverse causes are confirmed and drug-related telogen effluvia are reviewed.

Conclusions: The five diverse mechanisms proposed for telogen effluvia are generally confirmed and supported by clinical findings.