Telogen effluvium is characterized by increased telogen club hair shedding.
Telogen effluvium is the most common cause of diffuse hair loss.
Telogen effluvium is subdivided into acute telogen effluvium, chronic diffuse telogen hair loss, and chronic telogen effluvium.
Differential diagnoses include alopecia areata incognita and psychogenic pseudoeffluvium.
Spontaneous recovery can be expected once a cause is identified and eliminated.
Telogen effluvium (TE) was originally described by Kligman in 1961.1 TE is best characterized by a premature termination of the anagen (growing) phase of hair follicles, with a resultant increase in telogen (resting) phase hairs leading to excessive and diffuse loss of club hairs.1 Classically, TE refers to an acute hair loss subsequent to a variety of stresses including those caused by febrile diseases, childbirth, emotional disturbance, chronic systemic diseases, or the administration of heparin.1 TE can be a physiologic event in the newborn.1 Later studies revealed that the trigger and manifestation of TE were variable.2,3 TE represents the most common cause of diffuse hair loss.3 In clinics, truly diffuse hair loss is not often encountered.4 The most common reason bringing TE patients to the clinic is the increase in hair shedding after shampooing or brushing alone.4 Typically, TE is self-limiting, and full recovery can be expected once the specific causes are identified and corrected.3,4 However, especially in nonclassical chronic TE in women, distinction between female pattern hair loss is often challenging.5 In this chapter, the clinical features, pathophysiology, and differential diagnoses of TE are discussed.
Approximately, the loss of more than 25% of scalp hairs has been reported to be necessary to clinically detect diffuse hair loss.1 Therefore, most TE cases are likely to be subclinical, making estimation of its real incidence or prevalence quite difficult.2,4 Female predominance has been noted in TE, probably because of stronger awareness of daily hair conditions and more dynamic hormonal changes including menstruation and gestation.4,6 In theory, incidence of classic acute TE following known triggering events would not be distinct between the sexes.4 TE can occur in children but the incidence has been reported to be low.7 Elderly women are more likely to suffer from classic acute TE.4 Chronic TE (CTE) represents a unique form of unknown etiology that affects the whole scalp and is mostly seen in middle-aged women.8,9
Depending on the clinical course and symptoms, TE can be subdivided into 3 subgroups: classic acute TE,1 chronic diffuse telogen hair loss,2,4,10 and chronic telogen effluvium8,9 (Table 86-1). Irrespective of clinical subtypes, the most representative manifestation of TE is diffuse excessive shedding of club hairs.1,2,4,8...