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 universalis (AU) is a condition characterized by the complete loss of hair on the scalp and body. It is an advanced form of alopecia areata, a condition that causes round patches of hair loss. Although the exact cause of AU is unknown, it is thought to be an autoimmune condition in which an affected person's immune system mistakenly attacks the hair follicles.