Alopecia areata is a T cell-mediated autoimmune disease affecting the hair follicles. What this means is that immune system cells, called T cells, wrongfully recognize the cells of the hair follicles as foreign, and attack them.

The autoimmune attack causes inflammation in the hair follicles, which causes them to lose their hair, and lose the ability to regrow hair until the response is suppressed.

As with many autoimmune diseases, alopecia areata is unpredictable. There is no way to determine when the hair will fall out, how much will fall out, when it will grow back, and if the hair will last.

For many people, alopecia areata is cyclical – meaning they go through phases of hair growth and hair loss. Some people will regrow and maintain hair for many years before it falls out again, others will not regrow any hair on their own (without treatments). Though more common in children than adults, some individuals will only experience one episode of alopecia areata before it grows back and doesn’t fall out again.

Alopecia areata is a non-scarring alopecia, meaning that the hair follicles are NOT destroyed, and they are capable of regrowing hair if the autoimmune response is suppressed.

This unpredictability and lack of full understanding highlights the need to fund biomedical research so that the inner workings of the disease can be discerned.

Below are all known types of alopecia areata:

Localized alopecia areata: one or more patches of hair loss on the scalp. Sometimes referred to as patchy alopecia areata.

Alopecia barbae: one or more patches of hair loss in the facial hair.

Ophiasis alopecia areata: loss of hair on the sides and back of the scalp.

Sisaipho alopecia areata: loss of hair on the top of the head.

Alopecia totalis: loss of all the hair on the scalp.

Alopecia areata incognita: diffuse hair loss on the scalp – does not form full bald spots.

Alopecia universalis: loss of all the hair on the body including scalp, eyebrows, eyelashes, and body hair.