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.
What you need to know about alopecia areata. Alopecia areata is a common autoimmune skin disease, causing hair loss on the scalp, face and sometimes on other areas of the body. In fact, it affects as many as 6.8 million people in the U.S. with a lifetime risk of 2.1%. People of all ages, both sexes and all ethnic groups can develop alopecia areata.