Alopecia areata: what causes patchy hair loss, how it's treated, and whether a transplant can help

What is alopecia areata?

In alopecia areata, the immune system attacks hair follicles. The follicles are not destroyed, which is why hair can regrow, but while they are under attack they stop producing visible hair. The result is usually one or more round or oval bald patches that appear over a few weeks, most often on the scalp, though the beard, eyebrows, eyelashes and body hair can be affected too.

It is more common than many people think. A Mayo Clinic analysis of the Rochester Epidemiology Project estimated the lifetime risk of developing alopecia areata at 2.1%, with similar rates in men and women and the highest rates of new cases in people in their 20s and 30s. The average age at diagnosis was 31.5 for men and 36.2 for women (Mirzoyev et al., J Invest Dermatol, 2014). Children can develop it as well.

Symptoms and signs

• Smooth, round or oval patches of hair loss, often coin-sized, that appear fairly suddenly.
• "Exclamation point" hairs at the edge of a patch: short hairs that are narrower near the scalp, a sign that the condition is active (DermNet).
• Patches in the beard, eyebrows or eyelashes. Our beard transplant guide explains why a sudden patchy beard needs a diagnosis before any surgery.
• White or fair regrowth at first, because new hairs may initially lack pigment.
• Nail changes such as tiny pits or ridges, seen in an estimated 10% to 40% of patients and more common in severe disease (DermNet).

Types of alopecia areata

• Patchy alopecia areata: one or more round patches. This is the most common form.
• Alopecia totalis: loss of all scalp hair, affecting up to about 5% of people with the condition (DermNet).
• Alopecia universalis: loss of all scalp and body hair, affecting fewer than 1%.
• Ophiasis: a band of loss around the back and sides of the scalp. It tends to be harder to treat.
• Sisaipho: the reverse of ophiasis, with loss on the top and front. It can look like pattern baldness, which is one reason a proper diagnosis matters.
• Diffuse alopecia areata: sudden, widespread thinning rather than distinct patches.

Alopecia areata vs pattern hair loss

Most hair loss in men and women is pattern hair loss (androgenetic alopecia), which is inherited and hormone-related. The two conditions behave very differently:

If your loss follows the classic hairline-and-crown pattern, our Norwood scale guide and receding hairline guide will be more relevant. If it appeared suddenly in patches, see a dermatologist.

What causes it?

Alopecia areata is an autoimmune condition with a strong genetic component; researchers have identified at least 16 genetic risk regions. It is more common in people with other autoimmune or allergic conditions, including thyroid disease, vitiligo, psoriasis, diabetes and atopic conditions such as eczema and asthma (DermNet).

Many people link the start of a flare to a stressful period. In one French survey cited by DermNet, 65% of respondents attributed onset or worsening to stress. That is a common perception, not proof that stress is the root cause, and the condition often appears with no obvious trigger at all.

How it's diagnosed

The American Academy of Dermatology (AAD) notes that a board-certified dermatologist can often diagnose alopecia areata by examining the hair, scalp and nails. Many dermatologists use a handheld magnifier (trichoscopy) to look for exclamation point hairs, broken hairs and black dots, which suggest active disease. If the picture is unclear, your doctor may suggest tests to rule out other causes, such as fungal infection, thyroid problems or scarring forms of hair loss.

Treatment options to discuss with a dermatologist

There is no cure, but several treatments can help hair regrow or slow the loss. According to the AAD, options include:

• Watchful waiting for one or two small patches present for less than a year, since many regrow on their own.
• Corticosteroid injections into the patches, which the AAD describes as the most effective treatment for adults with a few patches.
• Corticosteroid creams or solutions, used in both children and adults.
• Minoxidil, used alongside other treatments to help maintain regrowth.
• Contact immunotherapy for widespread loss, with reported success rates ranging from 17% to 75%.
• JAK inhibitors, tablets that calm the immune signals involved. The FDA has approved three for alopecia areata: baricitinib and ritlecitinib for people aged 12 and older, and deuruxolitinib for adults, each for severe or extensive hair loss.
• Other oral immune-suppressing medicines in some cases.

Most of these are prescription treatments with side effects that need monitoring, and the right choice depends on how much hair is affected, your age and your other health conditions. Talk to a doctor or dermatologist rather than starting anything on your own. For brows and lashes, the AAD also mentions injections, microblading and artificial lashes, and wigs or scalp prostheses can help while you wait for regrowth; see our wigs guide.

Will my hair grow back?

Often, yes. The AAD says that "for many people, their hair regrows on its own without treatment," particularly with a few patches present for less than a year. Hair loss can also stop for long periods or come and go, and few people with extensive loss regrow hair without help. DermNet lists factors linked to a less favorable outlook: starting at a younger age, more extensive loss, loss lasting longer than a year, nail changes, the ophiasis pattern, a family history, and other autoimmune or allergic conditions.

The angle most guides skip: alopecia areata and hair transplants

Top-ranking guides cover symptoms and medicine but rarely answer a question we hear often: can a hair transplant fix it? In most cases, not while the condition is active. A 2024 review of pre-surgical considerations in hair restoration states that active alopecia areata is a contraindication to transplant surgery, because the transplanted hair may be affected, and that surgery may trigger a recurrence, a risk that is reduced but not eliminated when the disease is quiet (Tan, Yong & Wang, Plast Aesthet Res, 2024).

The reason is biological. Transplants work for pattern baldness because hair from the back of the scalp resists hormone-driven thinning and keeps that resistance after it is moved. Alopecia areata is different: the immune system can target follicles anywhere, including transplanted ones. The same review notes only a few case reports of successful transplants in long-quiet alopecia areata, and says patients should be told a flare can happen immediately or years later.

What this means in practice:

1. Get a confirmed diagnosis first. Sudden patchy loss, or the sisaipho pattern, can be mistaken for a receding hairline.
2. Expect a responsible surgeon to examine your scalp closely and to decline or postpone surgery if there are signs of active disease.
3. If you have a history of alopecia areata but long-term stability, ask the surgeon to coordinate with your dermatologist and to explain the recurrence risk in writing.
4. The same caution applies to beard and eyebrow transplants.

Our hairline transplant guide and best age for a hair transplant guide explain what makes someone a good surgical candidate.

When to see a doctor

See a doctor or board-certified dermatologist if you notice sudden round patches of hair loss, loss in your beard, eyebrows or eyelashes, new nail pitting, or patchy loss in a child. Because alopecia areata is linked with other autoimmune conditions, the AAD recommends keeping regular dermatology appointments. Hair loss can also take an emotional toll, and depression and anxiety are more common in people with the condition, so it is worth mentioning how you are feeling, not just how your hair looks.

Frequently asked questions