Telogen effluvium is a condition where more than normal amounts of hair fall out. There is a general 'thinning' of the hair. Unlike some other hair and scalp conditions, it is temporary and the hair growth usually recovers.
Hair is made in tiny pouches in the skin, called hair follicles. Each scalp hair has a normal life cycle. Most scalp hairs last about three years and grow about 1 cm a month. After a period of time (about three years), each hair on the scalp comes to the end of its life and falls out. The hair follicle rests for a short while. It then starts to make a new hair.
All the hairs on the scalp are at different stages in their life cycle. At any one time about 1 in 100 scalp hairs are at the end of their life ready to fall out. This is why you will commonly find a few hairs on your shoulders and some hairs fall out each time you wash your hair.
If you have telogen effluvium, a lot of hairs fall out from your scalp. This is more than normal and most noticeable when you wash your hair. However, your scalp and the remaining hair look healthy. You will not have patches of hair loss (bald patches) but rather a generalised thinning.
Telogen effluvium usually occurs about 1-3 months after a major stress to the body. The most common time it occurs is in women about 1-3 months after childbirth. Other times include 1-3 months after a major operation, accident, or illness.
A major stressful event such as childbirth or major surgery can interrupt and stop the growth of some hairs. It tends to affect older hairs which are brought to an end of their life cycle earlier than the usual three years or so. Many more hairs than usual are then ready to fall out. It takes 1-3 months for the affected hairs to fall out after their growth has stopped. After a short time, new hairs then grow from the hair follicles as usual. A normal pattern and thickness of hair returns within a few months once these new hairs are established.
However, persistent excess hair shedding may be caused by iron deficiency or an underactive thyroid gland. Your doctor may do a blood test to check for these if you have any other symptoms of these conditions.
No treatment is available or required in most cases. Once the stressful event has passed, your hair thickness will usually return to normal within a few months. Rarely, you may have telogen effluvium caused by zinc deficiency or iron deficiency and taking appropriate supplements cures the problem.