Why there is short thin hair fall after telogen effluvium?

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

Short thin hairs may be present for a few reasons. One would need to see the scalp to determine which it is. First,  short hairs may be the expected regrowing hairs that occurs in anyone after shedding. Over time, those hairs become longer and thicker elongating by 1 cm each and every month. Second, in some  cases these short hairs are vellus hairs that don’t really thicken up. The hairs stay somewhat short snd thin due to an acceleration of androgenetic alopecia. Accelerates follicular miniaturization after prolonged shedding is a term that describes this process. Third, in some cases, the diagnosis may be wrong and the short hair is actually occurring from a different reason. Be sure to see a physician to confirm or reevaluate if things don’t improve.

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.

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.