A desert is a region of land that is very dry because it receives low amounts of precipitation (usually in the form of rain but may be snow, mist or fog), often has little coverage by plants, and in which streams dry up unless they are supplied by water from outside the area.
Alopecia areata is an autoimmune disease. Autoimmune means that the body's immune system attacks the body. When alopecia areata develops, the body attacks its own hair follicles. A person's genetic makeup, combined with other factors, triggers this form of hair loss.
Types of Autoimmune Diseases. Alopecia Areata. Alopecia areata is triggered by the immune system attacking the hair follicles, leading to hair loss on the scalp, the rest of the body, or both. Most commonly, hair loss occurs in small patches, but in some people it can be much more extensive.