Everybody’s hair goes through a cycle. In fact, each hair follicle spends time producing a growing hair (the anagen phase), and then switches for a while into the inactive phase when the hair is made ready for shedding (the telogen phase). If we look at all the hair on someone’s head, at any one time about 90% of the hairs are growing and 10% are ready to shed.
Every day we shed about 50-100 hairs, quite normally. However sometimes the hairs can go into the same phase of the cycle, meaning that many of the hair follicles enter the telogen phase at the same time.
When this happens, increased and sometimes dramatic hair shedding can occur, called telogen effluvium, where the hair loosens, sheds and thins significantly.
A dermatologist should be able to identify telogen effluvium through talking to you, examination and investigations, including blood tests and sometimes a scalp biopsy, where a circle of skin about 4mm in diameter is taken from the scalp to look at the follicles under the microscope.
If telogen effluvium is confirmed it is usually reassuring news. Hair loss is likely to completely recover, although it may take up to a year for the this to happen.