Alopecia totalis is a skin condition that causes hair loss. It isn’t the same as localized alopecia areata. Localized alopecia areata causes round patches of hair loss on the scalp, but alopecia totalis causes complete baldness of the scalp.
Alopecia totalis is also different from the most severe form of alopecia areata, known as alopecia universalis. This form of alopecia causes complete hair loss over the entire body. The primary symptom of alopecia totalis is complete loss of all head hair. This form of alopecia can begin as alopecia areata. You may start off with small patches of hair loss. These patches spread over time until the entire head is bald.  Hair loss can begin suddenly and occur rapidly. If you have alopecia totalis, you may also have brittle, pitted nails.

Researchers and doctors aren’t yet able to pinpoint the exact cause of alopecia totalis, though it’s understand that the condition is the result of an immune system problem. Your immune system is your body’s defense mechanism that protects you from illnesses. But sometimes, the immune system attacks healthy tissue.  If you have any form of alopecia, your immune system attacks your hair follicles. This attack triggers inflammation, which leads to hair loss.

It's unclear why a person develops an autoimmune disease, but some people have a higher risk of alopecia totalis. It can affect anyone, but it’s more common in children and adults younger than 40 years.

Some people may also have a genetic predisposition for alopecia. It’s not unusual for someone with alopecia totalis to have a family member diagnosed with alopecia.

Some doctors also suspect a connction between extreme stress and developing alopecia. Chronic stress can weaken the immune system and interfere with its ability to function properly.