Hair diseases: 

Hair loss is called alopecia and is classified as either being cicatricial or non-cicatricial. Cicatricial alopecia is not reversible, in other words, the patient does not improve with traditional treatments. Non-cicatricial alopecia can be improved if identified early enough, however, treatment is long-term. Some examples of non-cicatricial alopecias are: alopecia areata, traction alopecia, telogen effluvium and androgenetic alopecia. 

Excessive hair growth in a female is called hirsutism and is usually treated by laser hair removal.