Alopecia, commonly known as baldness, is a set of disorders which involves the state of lacking hair where it would normally grow, especially on the head. The most common form of baldness is a progressive hair-thinning condition that occurs in adult humans and other primate species. Nonetheless, the severity and nature of condition can vary greatly; it ranges from male and female pattern alopecia (alopecia androgenetica), to alopecia areata, which involves the loss of some of the hair from the head, alopecia totalis, which involves the loss of all head hair, to the most extreme form, alopecia universalis, which involves the loss of all hair from the head and the body. Treatment for alopecia has limited success. The more hair lost, the less successful the treatment will be. The psychological implications of alopecia include stress, anxiety and depression, and can in many cases involve issues relating to identity change, particularly when the eyebrows and eyelashes are also lost. Hair loss is sometimes the result of chemotherapy treatment for cancer sufferers.

Table of Contents:
Male pattern baldness
Female pattern baldness
Mechanism of male pattern baldness
Evolutionary theories of male pattern baldness