ALOPECIA AREATA OVERVIEW
Alopecia areata is a auto-immune disease that causes a sudden loss of patches of hair on the scalp and sometimes other parts of the body. It is nonscarring, which means that there is no permanent damage to the hair follicle. In most people, new hair eventually grows back in the affected areas, although this process can take months. Approximately 50 percent of people with mild alopecia areata recover within a year; however, most people will experience more than one episode during their lifetime.
The estimated prevalence of alopecia areata is approximately 1 in 1000 people, with a lifetime risk of approximately 2 percent. About one person in 50 will suffer from alopecia areata at some point in their life (or 6 Million people in the US at the current census). For most patients the onset is before age 30; it occurs in men and women of all races equally. The condition can develop at any age, although most people develop alopecia areata for the first time during childhood.
Alopecia areata is not life threatening, and does not cause physical pain. However, the cosmetic effects of hair loss can be devastating.
ALOPECIA AREATA CAUSES AND RISK FACTORS
In alopecia areata, the body’s immune system mistakenly attacks the hair follicles for reasons that are not clear. Fortunately, the follicles retain their ability to regrow hair, and the hair loss is not permanent in most cases.
Other conditions can occur along with alopecia areata; these include vitiligo (a disorder that causes patchy whitening of the skin), thyroiditis (inflammation of the thyroid gland), and pernicious anemia (a decrease in the number of red blood cells due to a vitamin B12 deficiency).
Approximately 20 percent of people with alopecia areata have a family member who is also affected. Based on this, experts believe that some people have a genetic predisposition to the disease. A person who has a close relative with alopecia areata has a slightly increased risk of developing it as well. If the relative experienced hair loss before the age of 30, the risk is increased further.
ALOPECIA AREATA SYMPTOMS
People with alopecia areata typically have smooth, round patches of complete hair loss that develop over a period of a few weeks, followed in most cases by regrowth over several months. However, alopecia areata may persist for several years and sometimes hair never regrows.
The patches may enlarge and form bizarre patterns.
Short hairs, broken off a few millimeters from the scalp, are often found at the edges of expanding patches of hair loss. These are sometimes referred to as “exclamation point hairs.”
The scalp is the most common site for hair loss, but any area of the body can be affected. For many people, the disease does not progress beyond patchy hair loss. However, in some cases the hair loss is extensive. A small minority of patients lose all the hair on their head (known as alopecia totalis) or all the hair on their head and body (alopecia universalis).
ALOPECIA AREATA DIAGNOSIS
The diagnosis of alopecia areata is based upon the appearance of the hair loss. A healthcare provider will look for the characteristic patterns of hair loss, such as smooth patches with short, broken-off hairs around the borders.
Biopsy (the removal of a sample of tissue for study) is usually not necessary. Blood tests for thyroid disease or pernicious anemia may be recommended.
PSYCHOSOCIAL IMPACT OF ALOPECIA AREATA
Losing one’s hair can be a devastating experience, particularly because it develops suddenly and the loss is difficult to hide. Women and children frequently struggle with depression or low self-esteem as a result of their hair loss.
Patients who have difficulty with the psychosocial impact of losing their hair should speak to a healthcare provider about their feelings. Providers can offer support and may recommend that a patient work with a therapist, clinical psychologist, or support group; individual and group therapy can help patients adjust and cope with hair loss, and may also provide tips on cosmetic coverings.
ALOPECIA AREATA TREATMENT
Not all people with alopecia areata require treatment; many patients with limited disease will experience spontaneous hair regrowth.
For patients who use treatments, there are several options. However, alopecia areata cannot be “cured”. As noted above, most patients experience future episodes of hair loss.
Corticosteroids — Corticosteroids, commonly called steroids, are anti-inflammatory medications that are used to treat alopecia areata. They can be taken by injection, applied topically (as a cream or lotion), or taken by mouth.
Injected corticosteroids — This method of treatment is often recommended for adults with isolated patches of hair loss. The medication is injected directly into the affected area to stimulate hair regrowth. New growth is usually seen within four weeks; injections are repeated every four to six weeks until regrowth is complete. Because injections can be painful, the affected area may be pretreated with a topical anesthetic cream. The cream should be applied generously and covered with a tightly fitting shower cap or plastic wrap for 1.5 to 2 hours before treatment. The cream is removed immediately before injection.
Topical corticosteroids — Although topical corticosteroids (ointments, lotions, gels, creams, or foam) are often used, there is limited evidence to support their effectiveness. They may work best when used in combination with other topical treatments, such as minoxidil (see below), or injected corticosteroids.
Topical minoxidil — Available over-the-counter, topical minoxidil (eg, Rogaine®) promotes hair growth by lengthening the growth phase of hair follicles and causing more follicles to produce hair.
Minoxidilis approved to treat androgenetic alopecia (male pattern hair loss); it may also be useful in patients with mild alopecia areata. The solution is typically applied twice a day to the area of hair loss, and can be used alone or in combination with other therapies. When treatment is successful, new hair growth is seen in about 12 weeks. Minoxidil is not effective in patients with severe alopecia areata or total loss of scalp hair.
Anthralin — Anthralin is a treatment that was originally developed for the treatment of another skin condition, psoriasis, but was later found to regrow hair in some people with mild alopecia. It must be used with care because it irritates the skin and eyes and can stain fabrics. Hair regrowth may be seen within three to four months.
Treatment with anthralin is uncomfortable and of limited benefit.
Topical immunotherapy — Topical immunotherapy is probably the most effective treatment for patients with extensive or recurrent scalp involvement. This technique involves applying a substance known to cause an allergic reaction to the area of hair loss. The resulting itching, scaling, and irritation often induce hair growth for reasons that are not completely understood.
Topical immunotherapy is not widely available in the United States. Patients who are interested in trying it should see a dermatologist (physician specializing in the skin) who is experienced with this treatment. This therapy is available in Canada.
Photochemotherapy — In photochemotherapy, the person is given a light-sensitive drug (either applied to the skin or taken by mouth) and then exposed to an ultraviolet light source. Studies have shown conflicting results. However, a trial of photochemotherapy may be reasonable in people with extensive alopecia areata if topical immunotherapy is not available. Treatment is usually continued for four to six months.
COSMETIC APPROACHES TO ALOPECIA AREATA
Female patients with extensive alopecia areata usually opt to purchase a wig or hairpiece. An attractive wig is important for many women and children, although high-quality wigs can be expensive. Wigs can be cut and styled according to an individual’s preference and may be attached to the head with double-sided tape or a suction cap.
Men frequently opt to shave their scalp; wigs and hairpieces are generally less acceptable. Temporary tattooing can be helpful for the loss of eyebrows. False eyelashes are an option for patients with hair loss involving the eyelashes.
ALOPECIA AREATA PATHOPHYSIOLOGY
T-cell mediated perifollicular inflammation leading to disruption of the normal hair cycle has been implicated in the pathogenesis of alopecia areata. Unlike cicatricial alopecias (eg, lichen planopilaris or discoid lupus), the inflammatory process in alopecia areata does not lead to scarring and destruction of the hair follicle.
Disruption of the hair cycle — Hair follicles in normal skin cycle through periods of active hair growth (anagen), follicular involution (catagen), and follicular rest (telogen) (picture below). In alopecia areata, perifollicular inflammation is associated with dystrophic changes in anagen follicles and stimulates premature transition of anagen follicles to the nonproliferative catagen and telogen phases.
Autoimmunity — The association of alopecia areata with autoimmune diseases such as thyroiditis and vitiligo suggest an autoimmune etiology for this disorder. Theories for the mechanism of autoimmunity have included the following:
- Collapse of the immune-privileged status of hair follicles leads to a cell-mediated immune response that targets follicular antigens.
- Immune privilege does not extend to the catagen phase, and inflammatory cells that present during follicular regression inappropriately trigger an immune response against follicular antigens.
Although a cell-mediated immune response is thought to be primarily responsible for hair loss in alopecia areata, hair follicle autoantibodies are frequently present in sera from affected individuals. Whether these antibodies have a pathogenic role is uncertain.
Genetics — Genetic background influences risk for the development of alopecia areata. In a study of 206 patients with alopecia areata, 20 percent had a first degree relative with the disease. The importance of genetics is also supported by studies reporting high concordance rates among identical twins. In one study involving 19 sets of monozygotic twins, both twins were affected in 42 percent of twin sets. In contrast, among 31 pairs of dizygotic twins, only 10 percent shared the disease.
The genetic predisposition for alopecia areata is thought to be polygenic in nature, and the results of a genome-wide association study suggest that genes involved in the regulation of the innate and adaptive immune systems participate in the pathogenesis of this disease. In the study, genomic regions containing the CTLA4, IL-2/IL-21, IL-2RA, and Eos genes, all of which are involved in regulating the activation or proliferation of regulatory T cells, were identified as susceptibility loci for alopecia areata. A strong association also was detected in a region containing genes encoding ULBPs, molecules involved in the stimulation of natural killer, natural killer T, gamma delta T, and CD8+ lymphocytes.
In addition to these findings, the genome-wide association study confirmed previously reported associations of alopecia areata with human leukocyte antigen (HLA) genes. The HLA-DQB1*03 allele, among others, may be an important marker for susceptibility to the disease. Several susceptibility loci that have been associated with other autoimmune diseases (eg, CTLA4, IL-2/IL-21, IL-2RA) also were identified, indicating that alopecia areata may share a common pathway with other autoimmune diseases.
Other — A variety of factors, such as infections, drugs, and vaccinations, have been implicated in triggering episodes of alopecia areata. Some patients report severe stress, especially emotional stress, as a precipitating event, although many patients have no such history. Remote events, such as childhood trauma, have also been associated with the development of alopecia areata in adults
The following organizations also provide reliable health information.
- National Library of Medicine www.nlm.nih.gov/medlineplus/healthtopics.html
- American Hair Loss Council www.ahlc.org
- American Academy of Dermatology www.aad.org
REFERENCES
- Safavi KH, Muller SA, Suman VJ, et al. Incidence of alopecia areata in Olmsted County, Minnesota, 1975 through 1989. Mayo Clin Proc 1995; 70:628.
- Tosti A, Iorizzo M, Botta GL, Milani M. Efficacy and safety of a new clobetasol propionate 0.05% foam in alopecia areata: a randomized, double-blind placebo-controlled trial. J Eur Acad Dermatol Venereol 2006; 20:1243.
- Price VH. Double-blind, placebo-controlled evaluation of topical minoxidil in extensive alopecia areata. J Am Acad Dermatol 1987; 16:730.
- Madani S, Shapiro J. Alopecia areata update. J Am Acad Dermatol 2000; 42:549.
- MacDonald Hull SP, Wood ML, Hutchinson PE, et al. Guidelines for the management of alopecia areata. Br J Dermatol 2003; 149:692.
Author, Andrew G Messenger, MD, FRCP
Last literature review version 19.3: September 2011 | This topic last updated: September 1, 2010 (More)