Alopecia areata is characterized by patchy scalp 
hair loss which occasionally affects every hair follicle on the scalp 
(alopecia totalis), or body (alopecia universalis).
The disease usually occurs between the the ages 
of adolescence and 30 years, but can appear at any age, affecting both 
sexes equally. Alopecia Areata has a rapid onset but tends to 
spontaneously reverse.
The cause of Alopecia Areata is unclear, however,
 genetic factors, auto-immune mechanisms, and the occurrence of 
stressful and/or emotional problems shortly before the hair loss are all
 thought to influence the condition.
Treatments for the disease include topical 
sensitizers, steroid shots, squaric acid dibutyl ester, diphencyprone, 
and hypnotherapy.
