Telogen Effluvium often occurs after some sort of stress, various medical conditions or pregnancy which causes some actively growing hair follicles to prematurely shift into a regression phase followed by a resting phase. It is during this time that the hair falls out. Often weeks to months pass after the stressful event which is usually what we call telogen or resting phase before the shedding of hair becomes noticeable. Eventually, the hair follicles recover.
In Telogen Effluvium, when the number of hair follicles producing hair declines, there will be an increase in telogen stage hair follicles. This results in shedding or hair loss. Best, Dr. Emer
Telogen Effluvium cycles from hair group to hair group, from hair to hair. The reason that these cycle occur is not known but it seems to be coordinated with the sleep cycle of hairs which lasts, on average of 6 months before new hairs grow.