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 is alopecia areata?Alopecia areata is a type of hair loss that occurs when your immune system mistakenly attacks hair follicles, which is where hair growth begins. Experts do not know why the immune system attacks the follicles. Alopecia areata is most common in people younger than 20, but children and adults of any age may be affected.