Hair loss is a frequent problem in many different circumstances. Distribution, evolution and social environment defines the nature of the alopecia and its prognosis.
We define alopecia as an excessive hair loss, above 100 hairs a day. Either women or men may be involved with a wide variety of causative factors, some genetic specially vulnerable to sexual hormones.
Alopecia areata, is an uncommon loss of hair, in definite areas of the skull or body, due probably to an autoimmune reaction.