Causes and Risk Factors of Alopecia Areata
Health ConditionsSkin ConditionsAlopecia

Causes and Risk Factors of Alopecia Areata

Causes and Risk Factors of Alopecia Areata
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Updated on July 21, 2025
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Alopecia is the clinical term for hair loss. Alopecia areata (AA) refers to a condition in which hair loss is fueled by your immune system mistakenly attacking your hair follicles.

AA is one of many types of autoimmune diseases, but research hasn’t yet identified a single cause for the hair loss that characterizes alopecia areata. Several risk factors such as family history of autoimmune disease, race and ethnicity, and environmental factors can affect a person’s risk of developing AA.

Alopecia areata can be lifelong, with symptoms occurring in cycles of hair loss and regrowth.

 Sometimes, hair loss is limited to a few patches on the scalp. At other times, the hair loss may be more extensive.

What Is Alopecia Areata?

Board-certified dermatologist Kristen Lo Sicco, MD, discusses some of the specific features of this type of alopecia.
What Is Alopecia Areata?

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Causes of Alopecia Areata

Despite what some may say, as an autoimmune disease, alopecia areata is not contagious.

There are more than 80 known types of autoimmune disease. In all autoimmune disease, the immune system mistakes healthy cells and tissues for invaders and attacks them to try and protect the body, triggering disease symptoms.

In AA, the immune system attacks the hair follicles, which are usually responsible for supporting hair growth. Hair follicles are like anchors for your hair: They extend into your top two layers of skin, called the dermis and epidermis, to support hair growth.

When these hair follicles become inflamed and do not function normally, such as when an immune system attack occurs, this can cause hair loss and make it difficult for the follicles to support new hair growth in their place.

The number of affected hair follicles and resulting hair loss also depends on the severity of the condition.

How quickly hair regrows depends on the person, the severity of the condition, and the site on the body where hair loss occurs. On the scalp, for example, the total growth phase of new hair can last two to six years.

Researchers do not yet know exactly what causes autoimmune disease. But experts believe autoimmune disorders like alopecia areata may develop from a combination of genetic and environmental factors, such as certain medications or exposure to microorganisms like bacteria and viruses.

Scientists also believe the genes associated with the development of AA may primarily trace back to the human leukocyte antigen (HLA) complex family of genes.

“Autoimmune conditions often travel in packs, so if you have one autoimmune disorder, such as thyroid or diabetes, it is not uncommon to have others,” says Brooke Jackson, MD, a board-certified dermatologist and dermatologic surgeon in Durham, North Carolina.

Many people develop alopecia areata alongside another type of autoimmune disorder, such as:

Risk Factors of Alopecia Areata

In many cases of AA–related hair loss, the onset of symptoms is abrupt and with no clear trigger. Still, in some cases, certain risk factors could influence alopecia areata’s development. If you have a genetic predisposition to alopecia areata, risk factors that could trigger the subsequent hair loss may include an injury, illness, or severe emotional stress.

“As with all autoimmune conditions, stress plays a key role in triggering the process,” Dr. Jackson says. “When we are stressed, our immune system does not function very well and is not fully capable of protecting us.”

It’s possible to develop AA at any age. Experts don’t consider age itself a risk factor for AA, but it most typically develops during childhood or early adulthood.

Also, adults who develop alopecia areata after age 30 are less likely to have a family member with this disease.

 Some studies suggest that Asian Americans, Black Americans, and Latin Americans are at greater risk of developing alopecia areata than white Americans.

Can Alopecia Areata Be Prevented?

Like other autoimmune diseases, alopecia areata can’t be prevented, and currently there is no cure. But many people with AA will see hair regrowth. For those who don’t see regrowth naturally, treatments such as oral and injectable medications are available.

If you have a family history of alopecia areata or other autoimmune disease, it may be worth discussing this with your doctor. Although autoimmune diseases aren’t preventable, your doctor may:

  • Physically examine you, including your nails and areas of hair loss
  • Discuss your medical and family history
  • Order blood work or other tests to help diagnose any immune-related disorders you may have

Early detection of autoimmune disease, including alopecia areata, means treatment can begin as soon as possible.

The Takeaway

  • Alopecia areata (AA) is an autoimmune disease in which the immune system attacks hair follicles, leading to hair loss. It’s not clear exactly what causes AA, but it’s thought to be a combination of genetic and environmental factors.
  • Regardless of the cause or trigger of alopecia areata, it’s important to see a dermatologist if you suddenly start losing your hair. They can help properly diagnose the condition and offer the best treatment methods to promote hair regrowth.
  • Treatments are dependent on several factors, including severity, a person’s age, and other related health conditions. Hair regrowth is possible for many people, both with and without treatment.

Resources We Trust

EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Alopecia Areata. Cleveland Clinic. August 30, 2023.
  2. Alopecia Areata. British Association of Dermatologists. April 2024.
  3. Alopecia Areata. National Organization for Rare Disorders. July 12, 2022.
  4. Ludmann P. Alopecia Areata Overview. American Academy of Dermatology Association. August 30, 2023.
  5. Autoimmune Disorders. MedlinePlus. June 12, 2023.
  6. Martel JL et al. Anatomy, Hair Follicle. StatPearls. June 22, 2024.
  7. Elshafy RAA et al. Alopecia Areata: An Overview of the Disease and Its Genetic Basis: Review Article. Egyptian Journal of Hospital Medicine. July 2022.
  8. Alopecia Areata. National Alopecia Areata Foundation.
  9. Alopecia Areata: Diagnosis, Treatment, and Steps to Take. National Institute of Arthritis and Musculoskeletal and Skin Diseases. August 2024.
Meet Our Experts
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Ross Radusky, MD

Medical Reviewer
Castle Connolly Top Doctor

Ross Radusky, MD, is a practicing board-certified dermatologist at the Dermatology Treatment and Research Center in Dallas. Originally from New York City, he graduated summa cum laude from the City University of New York and then received his MD from the New York University School of Medicine. There, he was inducted into the Alpha Omega Alpha Honor Medical Society and served as chapter president for two years. He completed his residency in dermatology at NewYork-Presbyterian Hospital and Weill Cornell Medical Center, and at Memorial Sloan Kettering Cancer Center.

Dr. Radusky practices general and cosmetic dermatology with a focus on the early detection of skin cancer, and provides patients with a personalized approach to looking their best at any age. He has authored articles and textbook chapters on the clues that our finger- and toenails may provide us about internal disease, as well as on comprehensive therapies for cosmetic dermatology and reversing the signs of skin aging.

Complementing his medical practice, Radusky has a strong passion for the cultural arts, particularly in expanding access to youths and seniors. He previously served as an artist instructor for the Rockaway Artists Alliance, a New York City nonprofit arts and education organization, and then served as both a board director and treasurer of the organization throughout his medical school training.

Radusky enjoys spending time outdoors with his wife Robyn, son Oliver, and poodle Lucy, where he can usually be found preventing photoaging and reducing the risk of skin cancer beneath an umbrella in a wide-brimmed hat. He is also the proud inventor of Sunshotz, the world’s only sunscreen measuring cup, designed to help patients of all ages apply the proper amount of sunscreen needed to enjoy all the sun without the burn.

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Kristeen Cherney, PhD

Author
Kristeen Cherney, PhD, is a freelance writer, essayist, author, and poet with more than 15 years of health writing experience for digital platforms such as Healthline, The Mighty, and LiveStrong. She’s covered nutrition, women’s and children’s wellness issues, as well as specialized topics ranging from diabetes and thyroid disease to anxiety, depression, asthma, allergies, and skin conditions.

With a doctorate in English (rhetoric and composition), Dr. Cherney focuses her academic scholarship on the intersection between disability and literacy. She also holds a Master of Arts in English and a Bachelor of Arts in communication.

Cherney has contributed to the books The Wiley Handbook on Violence in Education: Forms, Factors, and Preventions, Composing in Four Acts: Readings for Writers, and Georgia State University's Guide to First-Year Writing, as well as to scholarly journals like Praxis, the Journal of Teaching Writing, and the Journal of Dracula Studies.

Cherney enjoys running, meditating, hiking, and paddleboarding.
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