Alopecia areata is disease that primarily affects the immune system, causing it to attack the hair follicles. When this happens, hair falls out in clumps. The condition typically starts out with the patient developing a single bald patch. As the disease progresses, other bald patches may develop all over the head and join together into larger patches. In especially severe cases of alopecia, the patient may even lose all his hair.
The exact cause of alopecia areata is as yet uncertain, but its action on the immune system leads many to believe that it may be related to stress in some way. For reducing stress as a means to reduce the severity of alopecia areata, it may be beneficial to use medical marijuana.