|Classification and external resources|
Alopecia areata (AA) is a condition in which hair is lost from some or all areas of the body, usually from the scalp. Because it causes bald spots on the scalp, especially in the first stages, it is sometimes called spot baldness. In 1–2% of cases, the condition can spread to the entire scalp (alopecia totalis) or to the entire epidermis (alopecia universalis). Conditions resembling AA, and having a similar cause, occur also in other species.
- Hair may also be lost more diffusely over the whole scalp, in which case the condition is called diffuse alopecia areata.
- Alopecia areata monolocularis describes baldness in only one spot. It may occur anywhere on the head.
- Alopecia areata multilocularis refers to multiple areas of hair loss.
- The disease may be limited only to the beard, in which case it is called alopecia areata barbae.
- If the patient loses all the hair on the scalp, the disease is then called alopecia totalis.
- If all body hair, including pubic hair, is lost, the diagnosis then becomes alopecia universalis.
Alopecia areata totalis and universalis are rare.
Signs and symptoms 
Typical first symptoms of AA are small bald patches. The underlying skin is unscarred and looks superficially normal. These patches can take many shapes, but are most usually round or oval. AA most often affects the scalp and beard, but may occur on any hair-bearing part of the body. Different skin areas can exhibit hair loss and regrowth at the same time. The disease may also go into remission for a time, or may be permanent. It is common in children.
The area of hair loss may tingle or be painful.
The hair tends to fall out over a short period of time, with the loss commonly occurring more on one side of the scalp than the other.
Exclamation point hairs, narrower along the length of the strand closer to the base, producing a characteristic "exclamation point" appearance, are often present.
When healthy hair is pulled out, at most a few should come out, and ripped hair should not be distributed evenly across the tugged portion of the scalp. In cases of AA, hair will tend to pull out more easily along the edge of the patch where the follicles are already being attacked by the body's immune system than away from the patch where they are still healthy.
Alopecia areata is usually diagnosed based on clinical features.
Trichoscopy may aid differential diagnosis. In AA, trichoscopy shows regularly distributed "yellow dots" (hyperkeratotic plugs), small exclamation-mark hairs, and "black dots" (destroyed hairs in the hair follicle opening).
A biopsy is rarely needed in AA. Histologic findings include peribulbar lymphocytic infiltrate ("swarm of bees"). Occasionally, in inactive AA, no inflammatory infiltrates are found. Other helpful findings include pigment incontinence in the hair bulb and follicular stelae, and a shift in the anagen-to-telogen ratio towards telogen.
Alopecia areata is not contagious. It occurs more frequently in people who have affected family members, suggesting heredity may be a factor. Strong evidence of genetic association with increased risk for AA was found by studying families with two or more affected members. This study identified at least four regions in the genome that are likely to contain these genes. In addition, it is slightly more likely to occur in people who have relatives with autoimmune diseases.
The condition is thought to be an systemic autoimmune disorder in which the body attacks its own anagen hair follicles and suppresses or stops hair growth. For example, T cell lymphocytes cluster around affected follicles, causing inflammation and subsequent hair loss. A few cases of babies being born with congenital AA have been reported, but these are not cases of autoimmune disease, because an infant is born without a definitely developed immune system.
Also, some evidence indicates AA affects the part of the hair follicle associated with hair color. Hair that has turned gray may not be affected.
If the affected region is small, it is reasonable just to observe the progression of the illness, as the problem often spontaneously regresses and the hair may grow back.
In cases of severe hair loss, limited success has been shown from treating AA with the corticosteroids clobetasol or fluocinonide, corticosteroid injections, or cream. The cream however is not as effective and it takes longer in order to see results. Steroid injections are commonly used in sites where the areas of hair loss on the head are small or especially where eyebrow hair has been lost. Whether they are effective is uncertain. Some other medications used are minoxidil, Elocon (mometasone) ointment (steroid cream), irritants (anthralin or topical coal tar), and topical immunotherapy cyclosporine, sometimes in different combinations. Topical corticosteroids frequently fail to enter the skin deeply enough to affect the hair bulbs, which are the treatment target, and small lesions typically also regrow spontaneously. Oral corticosteroids decrease the hair loss, but only for the period during which they are taken, and these drugs have serious adverse side effects.
For small patches on the beard or head, suppression with topical tacrolimus ointments, such as Protopic, are possible. Symptoms may remain suppressed until aggravated by stress or other factors.
In one small study without a control group, diphenylcyclopropenone has shown a significant hair regrowth in 40% of patients with AA at six months, being sustained in two-thirds of these after a 12-month follow-up period. Whether this is significant remains doubtful; considerable spontaneous recovery occurs, as well.
To adapt to the disease rather than treating in an effort to cure, many options are also available. Wigs are often used by those with alopecia, particularly alopecia totalis, in which hair is entirely lost from the scalp. Wigs are available at many levels of development and technology, including wigs with suction mechanisms to keep them firmly attached to the scalp. However, there is no found cure yet.
A team of investigators at Columbia University, department of dermatology and genetics and development, has uncovered eight genes that underpin alopecia areata, one of the most common causes of hair loss. Since many of the genes are also implicated in other autoimmune diseases, including rheumatoid arthritis and type 1 diabetes - and treatments have already been developed that target these genes. According to Dr. Angela Cristiano, the lead author of the research, the genes responsible for the disease are nearly the same as those of patients with rheumatoid arthritis, Type 1 diabetes and celiac disease. The discovery may soon lead to new treatments for the 5.3 million Americans suffering from hair loss caused by alopecia areata.[not specific enough to verify]
Among the eight genes, one stands out for its potential role in the onset of alopecia areata. The gene, called ULBP3, is known to act as a homing beacon for cytotoxic cells that can invade and quickly destroy an organ. Normally, ULBP3 is not present in hair follicles, but its proteins are abundant in hair follicles affected by alopecia areata. The proteins attract cells marked by a killer cell receptor, known as NKG2D. In addition to ULBP3, two other genes are expressed in the hair follicle, while the five remaining genes are involved in the immune response.
Finding the initial genes underlying alopecia areata is a big step forward, but the nature of the genes is even more exciting," said Angela M. Christiano, PhD, professor of dermatology and genetics and development at Columbia University, and lead author of the study.[full citation needed]
Clinical trials 
The department of dermatology at the University of Columbia Medical Center have advised they are launching clinical trials of at least three medications:
- Abatacept (Orencia), which is FDA-approved for the treatment of rheumatoid arthritis
- A yet-to-be-named topical cream which inhibits cytokine activity, molecules that play a role in mediating the body's immune response
- Triamcinolone acetonide, which although already used for the treatment of alopecia areata, has never been rigoursly tested. They will also test the immunological changes associated with the drug.[full citation needed]
In most cases which begin with a small number of patches of hair loss, hair grows back after a few months to a year. In cases with a greater number of patches, hair can either grow back or progress to AA totalis or, in rare cases, AA universalis.
Effects of AA are mainly psychological (loss of self image due to hair loss). Loss of hair also means the scalp burns more easily in the sun. Loss of nasal hair increases severity of hay fever and similar allergic conditions. Patients may also have aberrant nail formation because keratin forms both hair and nails.
Hair may grow back and then fall out again later. This may not indicate a recurrence of the condition, however, but rather a natural cycle of growth-and-shedding from a relatively synchronised start; such a pattern will fade over time. Episodes of AA before puberty predispose one to chronic recurrence of the condition.
The condition affects 0.1%–0.2% of humans, occurring in both males and females. Alopecia areata occurs in people who are apparently healthy and have no skin disorder. Initial presentation most commonly occurs in the late teenage years, early childhood, or young adulthood, but can happen with people of all ages. Patients also tend to have a slightly higher incidence of conditions related to the immune system: asthma, allergies, atopic dermal ailments, and hypothyroidism.
See also 
- Alopecia totalis
- Alopecia universalis
- Noncicatricial alopecia
- Locks of Love
- List of cutaneous conditions
- Gail Porter - television presenter with alopecia totalis
- Joanna Rowsell - Olympic cyclist with alopecia areata
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- Duncan FJ. et al. (2013). "Endogenous Retinoids in the Pathogenesis of Alopecia Areata". Journal of Investigative Dermatology 133 (2): 334–343. doi:10.1038/jid.2012.344. PMC 3546144. PMID 23014334.
- Sotiriadis, D.; Patsatsi, A.; Lazaridou, E.; Kastanis, A.; Vakirlis, E.; Chrysomallis, F. (2006). "Topical immunotherapy with diphenylcyclopropenone in the treatment of chronic extensive alopecia areata". Clinical and Experimental Dermatology 32: 060927054804002–???. doi:10.1111/j.1365-2230.2006.02256.x. PMID 17004987.
- H. Panda: Handbook On Ayurvedic Medicines With Formulae, Processes And Their Uses 
- S. Suresh Babu: Homemade Herbal Cosmetics
- Science daily July 1 2010
- Columbia university medical center newsletter
- National Institute of Arthritis and Musculoskeletal and Skin Diseases at NIH
- DermAtlas 42
- National Alopecia Areata Foundation
- Canadian Alopecia Areata Foundation