What causes alopecia areata?

Alopecia is the medical term for baldness. There are many different conditions and diseases that can cause hair loss in both men and women, but alopecia is also the shorthand for an autoimmune disease.
Specifically, alopecia areata is a condition that causes patchy hair loss in some parts of your body. Other versions of this disease can cause hair loss across your entire body.
Healthy hair goes through periods where it’s actively growing followed by periods of rest. This cycle cannot progress normally, though, in people with alopecia. Instead, their immune system attacks the hair follicle and causes the strand to fall out. The hair can grow back later, but it doesn’t always.
More research will be needed to understand what causes the immune system to misbehave in these specific ways. There’s evidence from twin studies and observations of family history that some of the causes are genetic, but no comprehensive model has yet been proposed.
What are the types of alopecia?
There are a number of different ways that alopecia can present itself. The different versions of the disease are based on the location and extent of your hair loss.
Three of the main kinds are:
- Alopecia areata. This is the most common version of this condition. The hair loss occurs in small patches, usually on your scalp. It can also create small patches of hair loss in any other area where you grow hair.
- Alopecia totalis. This occurs when the patches of hair loss spread to encompass your entire head. You’ll become entirely bald.
- Alopecia universalis. This is a rare version of the disease that causes complete hair loss everywhere on your body. In this case, it’s unlikely that you’ll ever completely recover.
There are many other slight variations on the condition like “sudden graying”. This occurs when the alopecia only affects pigmented hair follicles and only your white or gray hairs are left intact.

Who can get alopecia?
Technically, anyone can develop alopecia at any time, but some people are more likely to get it than others. You have about a 2% risk of developing alopecia at least once in your lifetime. According to current research, there aren’t any differences in rates of alopecia between men and women.
The mean age of onset is between 25 and 36 years, though it can frequently occur in children and young adults too. Your version of alopecia is likely more severe if it begins between the ages of five and 10 years old.
You’re also more likely to get the condition if you have a family member with alopecia. Anywhere from 10% to 20% of people with the disease have a family member with the same condition.
Some diseases make it more likely that you will get alopecia. This includes autoimmune diseases and other types of conditions. Examples include:
How is alopecia diagnosed?
Alopecia can initially appear similar to other conditions.
Your doctor will ask about your medical and family history. They’ll also need to directly examine the bald patch.
Dermoscopy is a way to look closely at your scalp. Your doctor will be looking for black and yellow spots, broken hairs, and signs of newly growing hairs.
If a physical examination isn’t enough to positively diagnose your condition, you may need to undergo a biopsy. A biopsy is the extraction of a small physical sample that is helpful for diagnosing different conditions.
What are the symptoms of alopecia?
The main symptom of alopecia is hair loss. The first sign is usually the formation of a small, round bald spot on your head. The hair loss may spread from there. It can also affect other body parts that grow hair including your:
- Beard region
- Eyebrows
- Eyelids
- Armpits
- Inside your nose
- Inside your ears
There shouldn’t be any pain associated with the loss. You also shouldn’t see any signs of irritation or rashes in the area where the hair fell out, though some people report that they feel tingling or itchiness in a spot just before their hair falls out.
Your hair loss may come and go in waves. The hair even regrows on its own in many instances of alopecia. Then, it can fall out again with little warning. The symptoms of this condition are very unpredictable.
There are certain activities and situations, though, that may increase the frequency of your bouts of hair loss. These include:
- Cold weather — one study found that the colder months of October, November, and January all coincided with increased amounts of hair loss
- Emotional and physical stress
- Some vaccines
- Viral infections
- Drug use
There’s a 16% chance that you’ll have or develop another autoimmune condition along with your alopecia. Examples include:
- Lupus erythematosus
- Rheumatoid arthritis
- Inflammatory bowel disease
In 10% to 15% of alopecia cases, people also notice symptoms affecting their fingernails. You’ll likely have the most severe hair loss in cases where your nails are also affected. Symptoms affecting your nails can include:
- Dents and ridges
- Brittle nails
- Red nail beds

QUESTION
An average adult has about ________ square feet of skin. See AnswerWhat is the treatment for alopecia?
The treatment for alopecia depends on your age and the severity of your hair loss.
If you’ve had the condition for less than 12 months, your doctor will likely recommend a wait-and-see approach. Around 34% to 50% of all cases of alopecia areata reverse without any medical intervention. You just need to give the patches time.
Unfortunately, 14% to 25% of all cases of alopecia areata spread instead of clearing up. They progress into the more complete hair loss that defines alopecia totalis and universalis. There’s less than a 10% chance of recovery if your alopecia progresses to these advanced levels.
In these cases, or cases when your alopecia areata lasts longer than 12 months, the first treatment approach that doctors usually try are topical creams. No single treatment works for all cases, though, and none of them are totally effective at preventing future hair loss.
Triamcinolone acetonide is a corticosteroid that helps stimulate hair regrowth in 60% to 67% of cases of alopecia areata. Your doctor may also try a number of other topical creams and injectable corticosteroids if this one doesn’t work for you.
Oral medications aren’t usually prescribed because they can cause a lot of side effects, and there’s limited evidence of their usefulness.
You may also want to distract yourself (and others) from your hair loss. Some techniques include:
- Shaving your head or beard to hide the patches
- Wearing false eyelashes — this also helps protect your eyes
- Tattooing eyebrows
- Getting a wig — Locks of Love provides them at little to no cost to children with alopecia
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American Academy of Dermatology Association: "Hair Loss Types: Alopecia Areata Causes," "Hair Loss Types: Alopecia Areata Diagnosis and Treatment," "Hair Loss Types: Alopecia Areata Overview," "Hair Loss Types: Alopecia Areata Signs and Symptoms."
Cincinnati Children's: "What is Alopecia Areata?"
Columbia University Irving Medical Center: "New Treatments for Alopecia Areata."
Lepe, K., Zito, P.M. StatPearls, "Alopecia Areata," StatPearls Publishing, 2021.
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