Telogen effluvium (TE) is a pathogenically heterogeneous condition which so far has been classified into acute and chronic forms - or, according to Headington, into 5 different pathogenetic forms. Regrettably, Headington's classification is difficult to apply in the office, and most papers dealing with TE ignore it. The present review intends to propose a novel classification of TE and to introduce, tentatively, a new variety of TE. Three pathogenetic types of TE can be identified, whose common clinical element is the profuse shedding of hairs: (1) premature teloptosis, (2) collective teloptosis, and (3) premature entry into the telogen phase. In particular conditions, they may also be associated, as occurs in seasonal shedding and postpartum TE.
Keywords: Alopecia; Hair loss; Telogen effluvium; Teloptosis.