Suprabulbar Thinning of Hair in Telogen Effluvium

In the 2017 study, researchers investigated the phenomenon of suprabulbar thinning in hair shafts of individuals with telogen effluvium (TE), a condition characterized by excessive hair shedding. The study included 64 participants, divided into three groups: 21 with acute TE, 32 with chronic TE, and 11 healthy controls. The researchers collected telogen hair samples from participants and measured the diameters at the suprabulbar and mid-shaft levels of the hair. The results showed that the ratio of the diameter at the suprabulbar level to the mid-shaft level was significantly lower in the acute TE group (0.84±0.05) compared to the chronic TE group (0.89±0.07, p=0.004) and the controls (0.94±0.07; p<0.001). This finding suggests that suprabulbar thinning is a common change in acute TE and that this morphological feature is not unique to anagen effluvium (AE), as both TE and AE can exhibit similar hair shaft tapering. Therefore, suprabulbar thinning cannot be used to differentiate between AE and TE.