Alopecia Areata - Topic Overview
What is alopecia areata?
Alopecia areata is a type
hair loss that occurs when your
immune system mistakenly attacks
hair follicles , which is where hair growth begins. The damage to the follicle
is usually not permanent. Experts do not know why the immune system attacks the
follicles. Alopecia areata is most common in people younger than 20, but
children and adults of any age may be affected. Women and men are affected
What happens in alopecia areata?
usually begins when clumps of hair fall out, resulting in totally smooth, round
hairless patches on the scalp. In some cases the hair may become thinner
without noticeable patches of baldness, or it may grow and break off, leaving
short stubs (called "exclamation point" hair). In rare cases, complete loss of
scalp hair and body hair occurs. The hair loss often comes and goes—hair will
grow back over several months in one area but will fall out in another
When alopecia areata results in patches of hair loss, the
hair usually grows back in a few months.1
Although the new hair is usually the same color and texture as the rest of the
hair, it sometimes is fine and white.
About 10% of people with
this condition may never regrow hair.2 You are more
likely to have permanent hair loss if you:
- Have a family history of the
- Have the condition at a young age (before
puberty) or for longer than 1 year.
- Are prone to allergies
- Have extensive hair loss.
- Have abnormal color,
shape, texture, or thickness of the fingernails or toenails.
Because hair is an important part of appearance, hair
loss can result in feeling unattractive.
In some people with
alopecia areata, the fingernails and toenails become pitted—they look as if a
pin had made many tiny dents in them. They may also look like sandpaper.
Alopecia areata cannot be "cured" but it can be treated. Most people who
have one episode will have more episodes of hair loss.
How is alopecia areata diagnosed?
is diagnosed through a medical history and physical examination. Your doctor
will ask you questions about your hair loss, look at the pattern of your hair
loss, and examine your scalp. And he or she may tug gently on a few hairs or
pull some out.
If the reason for your hair loss is not clear, your
doctor may do tests to check for a disease that could be causing your hair
loss. Tests include:
- Hair analysis. Your doctor will take a
sample of your hair and examine it under a microscope. A scalp sample is also
- Blood tests, including testing for a specific
condition, such as an overactive or underactive thyroid gland (hyperthyroidism or