What is alopecia areata?
Alopecia areata is a disease that causes hair loss. In alopecia areata, the immune system attacks the structures in skin that form hair (hair follicles).
Alopecia areata usually affects the head and face, though hair can be lost from any part of the body. Hair typically falls out in small, round patches about the size of a quarter. In some cases, hair loss is more extensive.
Who gets alopecia areata?
Anyone can have alopecia areata:
- Both men and women can get it.
- It affects all racial and ethnic groups.
- It can happen at any age, but most people get it in their teens, 20s, or 30s.
If you have a close family member with the disease, you may have a higher risk of getting it, but for many people, there is no family history.
People with certain diseases, such as psoriasis, and those with allergic conditions such as hay fever are more likely to get alopecia areata.
What are the types of alopecia areata?
There are three main types of alopecia areata. In the most common type, hair loss happens in one or more coin-sized patches on the scalp or other parts of the body.
What are the symptoms of alopecia areata?
Alopecia areata mostly affects hair, but in sometimes it can cause changes to the nails. People with the disease are usually healthy and have no other symptoms.
Alopecia areata typically begins with sudden loss of round or oval patches of hair on the scalp, but any part of the body may be affected, such as the beard area in men, or the eyebrows or eyelashes.
After a bare patch develops, several possible things may happen:
- The hair grows back within a few months. It may look white or gray at first but may regain its natural color over time.
- More bare patches develop. Sometimes hair grows back in the first patch while new bare patches form.
- Small patches join to form larger ones.
- In rare cases, all body hair is lost.
In most cases, the hair regrows, but more hair loss may follow.
Nail changes such as ridges and pits occur in some people, especially those who have hair loss over more parts of their body.
What causes alopecia areata?
In alopecia areata, the immune system mistakenly attacks hair follicles, causing hair loss. Doctors do not know why the immune system attacks hair follicles, but they believe that both your genes and environmental factors play a role.