Alopecia Areata

Reviewed/Revised Oct 2024
VIEW PROFESSIONAL VERSION
Get the full details

What is alopecia areata?

Alopecia areata is the sudden loss of patches of hair without any of the obvious causes.

  • Your hair falls out in patches for no clear reason

  • Alopecia areata is common and happens most often in children and young adults

  • The hair loss is usually from the scalp or beard

  • Your fingernails may become rough and pitted

What causes alopecia areata?

Doctors think alopecia areata is an autoimmune disorder. In an autoimmune disorder your immune system mistakenly attacks part of your body. In alopecia areata, your immune system attacks your hair follicles so hair doesn't grow.

What are the symptoms of alopecia areata?

Alopecia areata causes:

  • Round patches of missing hair—patches can be small or you can lose all the hair on your scalp

You may notice short, broken hairs at the edges of the patches. You may have rough and pitted nails. There are no other symptoms, and you otherwise feel well.

How do doctors treat alopecia areata?

Alopecia areata sometimes gets better without treatment. The hair usually grows back in several months. If you have widespread hair loss, it’s less likely that your hair will regrow.  

Doctors treat alopecia areata with:

  • Corticosteroids injected at the bald spots

  • Sometimes, chemicals applied to the bald spot to mildly irritate it (this can cause hair growth)

Drugs Mentioned In This Article
quizzes_lightbulb_red
Test your KnowledgeTake a Quiz!
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID
Download the free Merck Manual App iOS ANDROID