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.
Alopecia areata is an autoimmune skin disease that results in hair loss on the scalp and elsewhere on the body. It occurs when your immune system mistakenly attacks hair follicles, which is where hair growth begins. It is not permanent, but experts do not know the cause of the attack on the hair follicles.