This is why there is a limit to the length hair can grow, and why dead hairs frequently appear on hairbrushes and combs. Healthy adults normally shed between 50 and 100 hairs each day. The condition of the hair and scalp, reflects the general well-being of the body and mind. The hair usually regrows, but the colour may be different. Generalised alopecia, in which all the hair drops out and and does not regrow, is rare.
Lice thrive in clean hair and they often spread among family members and in schools.
As you grow older, less pigment is deposited in hair shafts as they grow, and grey hairs appear. These usually start appearing at the temples, then gradually spread over the rest of the scalp. However, the speed and extent of greying depends much upon hereditary factors. However, there are some ailments which can cause abnormal hair loss. Women sometimes lose hair due to hormonal changes after childbirth, or after giving up using the contraceptive pill.