Alopecia areata (aka alopecia) is a disorder that causes hair loss. The amount of hair loss can range form a few isolated spots of hair loss on the scalp to a more extensive loss of hair. While the exact cause is unknown, it’s usually considered to be an auto-immune disorder, where a person’s immune system winds up attacking their hair follicles. Alopecia was recently brought into the spotlight after the Will Smith/Chris Rock incident at the 94th Academy Awards. Chris Rock made a joke regarding Jada’s shaved head, which led to an altercation.