Alopecia areata (patchy baldness) is a relatively common, non-contagious autoimmune disease that causes hair loss. It can occur on the scalp or other parts of the body in both men and women.
The cause of alopecia areata is unknown. It typically occurs first in childhood, and appears as one or more round bald patches on the scalp approximately the size of a quarter. The patches typically occur suddenly.
In most instances, alopecia areata does not progress beyond a few bald patches. However, complete baldness of the head (alopecia areata totalis) or complete hair loss on the head, face and body (alopecia areata universalis) may occur in very rare cases. Some individuals may also develop "pits" or "dents" in the fingernails as a result of the disease.
Each person sheds and regrows hair daily. Hair loss results when more hairs are being shed than regrown. Unlike animals, humans have a distinct pattern of growing, resting and shedding hair. Humans have a distinct number of terminal hair follicles at birth. These follicles grow and shed hairs in cycles.
During the normal cycle of hair growth, approximately 90 percent of the hair on a person’s scalp is growing at any one time. This growth (anagen) phase may last several years, with each hair growing about one centimeter per month during this time. When hair stops growing, it enters a resting (telogen) phase of three to four months. Hair is released from the hair shaft and shed from the scalp, initiating the next cycle of growth. Each day about 75 hairs are lost from a healthy person’s head.
The National Institutes of Health (NIH) estimates that alopecia areata affects approximately 4 million Americans at some point in their lives. Instances of the disease are commonly noted in people of both genders and of all ages and ethnic backgrounds. Alopecia areata is not painful or life-threatening and patients are often generally healthy otherwise.
Alopecia areata generally occurs in two forms:
A mild form where less than 50 percent of scalp hair is lost
An extensive form where greater than 50 percent of scalp hair is lost
The majority of patients with alopecia areata have the more mild form of the disease. Treatment results tend to be less effective for patients with extensive hair loss.
Risk factors and causes of alopecia areata
Alopecia areata (patchy baldness) is a noncontagious, autoimmune disease in which white blood cells release chemical messengers known as cytokines to attack healthy cells located in hair follicles. This shrinks the follicle to a point where hair production is considerably reduced. However, new follicle cells being produced naturally by the body are not affected, making hair regrowth possible in all cases.
Exactly why alopecia areata occurs is unknown. Some research suggests a combination of certain genes may make some people more likely to develop the disease. It may be that some sort of biological (e.g., virus) or emotional trigger (e.g., stress) initiates alopecia areata in people genetically predisposed to the disease. People with family members affected by the disease have an increased risk for exposure, particularly if the initial hair loss occurs before the age of 30.
Children with the disease do not usually have a parent with the condition. It is generally believed that several genes cause alopecia areata. This makes it unlikely that a child born to one or both parents with alopecia areata would inherit all of the necessary genes to develop the disease. In addition, twins with identical genes that cause alopecia areata often do not develop the disease in unison, suggesting other factors besides genetics may play a role in how the disease is triggered.
People with asthma, thyroid disease or certain allergic conditions (e.g., atopic eczema, hay fever) are also at increased risk for alopecia areata. The condition also occurs more frequently in people with a family history of these conditions or other autoimmune diseases (e.g., diabetes, rheumatoid arthritis, vitiligo). However, patients with alopecia areata do not usually have other autoimmune diseases themselves. The condition is also common in people with Down syndrome or other chromosomal disorders.
Signs and symptoms of alopecia areata
Signs and symptoms of alopecia areata may vary depending on the individual, and include:
Minimal hair loss, followed by regrowth with the condition never recurring
Loss and regrowth of hair indefinitely
Hair loss confined solely to the scalp
Hair loss on the face and body
Hairs tapered near the scalp (exclamation point hairs)
Some patients also report a tingling sensation, itching or mild pain at the site of an affected area.
Diagnosis methods for alopecia areata
Alopecia areata can be diagnosed by a physician. In addition to taking a medical history and performing a physical examination, inspecting the scalp and pattern of hair loss is often sufficient to diagnose alopecia areata or a similar disorder (e.g., male pattern baldness, androgenetic alopecia). Hairs may also be tugged or pulled out to determine hair strength.
If a diagnosis is not clear, a physician may take a sample of hair and scalp for laboratory analysis (biopsy). In some cases, blood tests may be used to test for other medical conditions that cause hair loss (e.g., overproduction of thyroid hormone [hyperthyroidism]).
Treatment and prevention of alopecia areata
Treatment of alopecia areata is not necessary because the condition is not dangerous to a patient’s overall health. However, the disease can have an emotional impact, which may improve through treatment. Recurrent hair growth followed by hair loss is common in people with alopecia areata. There is no cure for the disease, nor are there any specifically approved treatments.
Hair regrowth is always possible for patients, regardless of the severity of hair loss, because follicle production is not affected. Regrown hair is often white and very fine at first, but over time it regains most or all of its normal color and texture. Regrowth of all the hair may take months or years.
Although they do not prevent new bald patches, some medications approved for other purposes may be useful in regrowing hair, including:
Anti-inflammatory drugs that reduce pain and swelling. These allow hairs to regrow by decreasing the activity of the white blood cells attacking the follicles. Corticosteroids suppress the immune system and may be administered to treat alopecia areata in three ways:
Local injection. Hairless patches on the scalp or other areas (e.g., beard) may benefit from the injection of corticosteroids. The injections provide small doses of cortisone to the affected areas, allowing hair to grow. Large, hairless areas typically are not treated this way for a variety of reasons (e.g., number of shots required, increased risk of side effects).
Oral corticosteroids. These are often used to treat cases of more extensive hair loss. Due to the possibility of certain serious side effects (e.g., cataracts, high blood pressure, loss of bone density) oral corticosteroids are typically used over relatively short periods of time.
Topical ointments. Alopecia areata may be treated with ointments or creams containing corticosteroids. However, they tend to be less effective than injections or oral corticosteroids.
A treatment that may be effective for patients with severe alopecia areata. A liquid solution is administered to the scalp once a week, with the concentration of the solution increasing at each session until a mild allergic reaction occurs. Recipients of this treatment frequently experience hair regrowth, though many experience relapses in hair loss as well. Topical immunotherapy may cause certain side effects in some patients (e.g., rash, swollen lymph nodes).
Minoxidil (a type of vasodilator [drug used to expand arteries])
A topical solution approved by the U.S. Food and Drug Administration (FDA) to treat hair loss in men and women. Minoxidil may also be effective at growing hair in patients with alopecia areata. When effective, new hair usually grows within about 12 weeks. Minoxidil must be continually used in order to be effective. Any hair growth experienced will fall out if the use of the drug is discontinued.
An oral drug used to slow hair loss and sometimes regrow hair. Finasteride inhibits the conversion of testosterone into dihydrotestosterone (DHT), a hormone that shrinks hair follicles. Like minoxidil, the drug must be used continually in order to be effective. Finasteride cannot be used by women who are or may become pregnant due to a risk of birth defects in male fetuses.
A tar-like substance that suppresses immune function in the skin. Approved to treat psoriasis, anthralin may also be used to treat alopecia areata in some cases. It is applied topically to the affected area for short periods of time (approximately 20 minutes to one hour). When effective, results may take as long as eight to 12 weeks. It is often used in combination with other treatments (e.g., minoxidil, corticosteroids) for better results.
Often used to treat other autoimmune diseases (e.g., psoriasis, rheumatoid arthritis). Sulfasalazine suppresses the body’s immune system and may be effective in treating alopecia areata. Although this medication may help patients regrow hair, it increases the risk of infection and other serious side effects (e.g., skin cancer). Sulfasalazine may not be the preferred treatment for most patients.
A type of therapy that uses drugs, which increase the skin's sensitivity to ultraviolet radiation (photosensitizing agents), followed by exposure to light. Many people receiving photochemotherapy to treat alopecia areata experience hair regrowth. However, many patients undergo treatments several times per week for it to be effective. Photochemotherapy also carries an increased risk for serious side effects (e.g., skin cancer).
The cause of alopecia areata is unknown, making prevention of the disease impossible. Limiting stress may be beneficial for predisposed individuals, as stressful events may have a triggering effect. In addition, taking some preventative measures may minimize the embarrassment and dangers of extensive hair loss.
These measures include:
Applying sunscreen. Exposed areas of the scalp and face may scar or burn when exposed to harmful sunlight. Liberal application of sunscreen can help minimize this risk.
Wearing eyeglasses and sunglasses. In addition to protecting eyes from the sun, sunglasses can guard the eyes from harmful debris if eyebrows or eyelashes are missing. Eyeglasses also shield the eyes.
Use of hats, wigs and scarves. Wearing these items will protect the scalp from harmful sunlight while keeping the head warm.
Use of cosmetics. Colored powders and creams can be applied to the scalp to camouflage areas where hair is missing. Eyebrow pencil can also be used to hide missing eyebrows.
Because hair loss can take an emotional toll on a person, patients may benefit from joining an alopecia areata support group. Counseling from a mental health professional can also help boost a patient’s self-esteem.
Alopecia areata Medication
Questions for your doctor on alopecia areata
Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctors the following questions about alopecia areata:
Is it possible my hair loss could be the result of something other than alopecia areata?
What methods will you use to determine the cause of my hair loss?
Does alopecia areata pose a danger to my overall health?
Is my hair loss permanent?
If my hair grows back is it likely to fall out again?
What are my treatment options? How effective are they?
What side effects may occur from my alopecia areata treatments?
Am I likely to lose hair on other parts of my body as well?
Are there products available to help me camouflage the areas of hair loss?
Are my children likely to have alopecia areata as well?
What might complicate it?
The condition can have disturbing psychological consequences. The unpredictable course of the disease can be confusing and discouraging to the individual.
The disease is highly variable, with periods of spontaneous recovery and/or relapse. Individuals with patchy alopecia areata can usually expect regrowth of loss hair. If the individual has a history of atopic dermatitis or asthma, regrowth of loss of hair is less likely.
Other possibilities are male pattern baldness, lichen planopilaris, discoid lupus erythematosus, folliculitis decalvans, fungal infection, and alopecia due to radiation or other skin damage.