It appears to affect men and women equally.
In 8 out of 10 people, the hair grows back spontaneously within a year.
Alopecia areata causes hairless patches on the scalp.
In a person with alopecia areata, smooth, round patches of hair loss appear over a few weeks. It usually affects the scalp, but patches can appear on other parts of the body.
Early signs include raised spots, or follicular papules, which appear in reddened plaques or patches, about 1 inch across, but sometimes bigger.
It may start with one or more lesions, or with a single lesion that develops to multiple lesions over several weeks or months.
As the lesion affects the follicles, hair loss often results.
Abnormalities may also appear in the fingernails and toenails.
In some cases, the hair grows back, but symptoms may recur. For some people, the hair does not grow back, even after other symptoms have disappeared.
Alopecia areata is not contagious. It is an autoimmune condition, in which the immune system attacks the hair follicles, mistaking them for pathogens such as bacteria.
Most people with the condition are otherwise healthy and have no skin problems. It can happen at any age, but it is more likely to start during the late teenage years, early childhood, or early adulthood.
A genetic link means it can run in families. Around 20 percent of people with the condition have a family member who also has it.
It is more likely if a close relative develops patches before the age of 30 years. If a parent has it, there is a 50 percent that their offspring will too.
With early treatment, alopecia areata can be reversible. About 80 percent of people with the condition find that their hair regrows without treatment within a year.
Alopecia can cause emotional distress, but using a wig or shaving the head can ease these difficulties.
If hair does not regrow, some treatments are possible.
Steroid injections: these may help resolve small patches of hair loss. A steroid solution is injected straight into the scalp, several times. The steroid stops the immune system from attacking hair follicles.
After about 4 weeks, this treatment may stimulate regrowth. An individual might repeat treatment every few months. Hair growth may be permanent or temporary.
Topical steroids (creams and ointments) and steroid tablets: Physicians will widely prescribe these for alopecia areata, but their long-term benefits remain unclear.
Hair may regrow, but adverse effects include diabetes, stomach ulcers, itching, and sometimes hair growth in other areas. The longer a treatment lasts, the higher the chance of side effects.
Immunotherapy: This is the most effective treatment for total hair loss. The patient applies diphencyprone (DPCP) to the hairless skin once a week, in gradually increasing doses. Hair starts to regrow after about 3 months among patients who respond.
Adverse effects may include an allergic reaction, mild dermatitis, or eczema, or a severe skin reaction. Reducing the rate of dosage increase may help. Rarely, a patient may develop vitiligo, or patches of pigmentation. Hair may continue to fall out after treatment stops.
Dithranol cream: This is less effective than immunotherapy, and there is a greater risk of a skin reaction and itchiness. It can also stain the scalp and hair.
UV light treatment: two to three sessions of light therapy each week, usually in the hospital, may bring benefits after about 12 months. However, response rates are limited.
Minoxidil may have some benefit.
A systematic review published by Cochrane concluded that there is no reliable, safe, effective, long-term treatment for alopecia areata.
People who feel embarrassed about their hair loss can try the following.
- choosing a hairstyle that covers up patches
- wearing a wig, hairpiece, scarf, or cap
- shaving the head
- filling in eyebrows with makeup or a tattoo, known as dermatography
Alternative therapies such as aromatherapy, massage, or acupuncture have not yet been proven effective against alopecia.
Alopecia areata can be challenging for the person who experiences it. However, it is often temporary, and it may be treatable.
Anyone who is worried about unusual hair loss should ask their doctor for advice, or seek out a local support group.
Alopecia refers to any type of hair loss.
Alopecia areata means localized hair loss, or "hair loss in areas."
Small, soft, hairless patches appear, usually round or oval in shape. The scalp and beard are most commonly affected, but it can occur in any part of the body that normally has hair.
There may be tingling, or slight pain in affected areas. Hair may grow back in some parts of the body, temporarily or permanently.
When the hair falls out on the scalp, it tends to do so over a short period, and more so on one side than the other.
People with this type of alopecia have hairs that become narrower along the length of the strand closer to the base.