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Hair loss types: Alopecia areata causes

What causes alopecia areata?

Alopecia areata is an autoimmune disease. This means that your immune system mistakenly attacks a part of your body.

When you have alopecia areata, cells in your immune system surround and attack your hair follicles (the part of your body that makes hair). This attack on a hair follicle causes the attached hair to fall out.

The more hair follicles that your immune system attacks, the more hair loss you will have.

It’s important to know that while this attack causes hair loss, the attack rarely destroys the hair follicles. This means that your hair can regrow. The less hair loss you have, the more likely it is that your hair will regrow on its own.

Can a vitamin D deficiency cause alopecia areata?

Studies have found that people with certain autoimmune diseases, such as multiple sclerosis or rheumatoid arthritis, have a vitamin D deficiency.

Because alopecia areata is an autoimmune disease, scientists have looked at the vitamin D levels in people who have alopecia areata. Some people did have a vitamin D deficiency, but others didn’t. More research is needed before we know whether low levels of vitamin D play a role in causing this disease.

Who gets alopecia areata?

While anyone can get alopecia areata, some people have a greater risk of developing it. Those most likely to get it have:

  • A close blood relative with alopecia areata: It’s estimated that about 10% to 20% of people with alopecia areata have a family member who has it. Because many people try to hide hair loss, this percentage may be higher.

  • Asthma, hay fever, atopic dermatitis, thyroid disease, vitiligo, or Down syndrome: Research shows that people who have one of these diseases are more likely to get alopecia areata.

  • Been treating cancer with a drug called nivolumab: While it’s too early to say whether this greatly increases your risk, a few cancer patients who received a drug called nivolumab (nye-VOL-you-mab) have developed alopecia areata. The drug is used to treat lung cancer and melanoma that has spread. Hair loss usually begins a few months after they start treatment. It’s called nivolumab-induced alopecia areata, and the hair loss is considered a good sign. This type of hair loss usually means that the drug is working.

    You can treat this hair loss with a corticosteroid that you apply to the bald spots. It allows the hair to regrow without stopping cancer treatment.

Your race may also affect your risk of getting alopecia areata. In a large study, researchers found that black and Hispanic nurses were more likely than non-Hispanic white nurses to develop this disease.

While this study spanned several years, it has many limitations. For example, it only looked at women nurses in the United States. More research is needed to know whether this finding holds true for other people.

When does alopecia areata begin?

You can get alopecia areata at any age; however, most people develop it by 30 years of age. For many, the disease begins during childhood or the teenage years.

Alopecia areata often begins before your 30th birthday

Alopecia areata often develops during childhood or the teenage years.

group of teens

Is alopecia areata curable?

It cannot be cured; however, it’s possible to regrow hair. For some people, regrowth will happen without any help. Because alopecia areata cannot be cured, people who have regrowth can have more hair loss later. Some people have cycles of hair loss and regrowth.

If your hair doesn’t regrow on its own, medical treatments may help.

There are many treatments for alopecia areata, and scientists are studying new possibilities. To see the treatment options, go to Alopecia areata: Diagnosis and treatment.

Getty Images

Korta DZ, Christiano AM, et al. “Alopecia areata is a medical disease.” J Am Acad Dermatol. 2018;78:832-4.

Lakhmiri M, Cavelier-Balloy B, et al. “Nivolumab-induced alopecia areata: A reversible factor of good prognosis?” JAAD Case Reports. 2018;4:761-5.

Lee S, Lee H, et al. “Comorbidities in alopecia areata: A systematic review and meta-analysis.” J Am Acad Dermatol. 2019;80:466-77.

Paus R, Olsen EA, et al. “Hair growth disorders.” In: Wolff K, Goldsmith LA, et al. Fitzpatrick’s Dermatology in General Medicine (seventh edition). McGraw Hill Medical, New York, 2008:764.

Strazzulla LC, Wang EHC, et al. “Alopecia areata: Disease characteristics, clinical evaluation, and new perspectives on pathogenesis.” J Am Acad Dermatol. 2018;78:1-12.

Thompson JM, Park MK, et al. “Race and alopecia areata amongst US women.” J of Investigative Dermatology Symposium proceedings. J Investig Dermatol Symp Proc. 2018;19:S47-S50.

Tsai TY, Huang YC. “Vitamin D deficiency in patients with alopecia areata: A systematic review and meta-analysis.” J Am Acad Dermatol. 2018;78:207-9.