Alopecia areata, also known as spot baldness, is a condition in which hair is lost from some or all areas of the body.[12][1] It often results in a few bald spots on the scalp, each about the size of a coin.[7]Psychological stress and illness are possible factors in bringing on alopecia areata in individuals at risk, but in most cases there is no obvious trigger.[7] People are generally otherwise healthy.[7] In a few cases, all the hair on the scalp is lost (alopecia totalis), or all body hair is lost (alopecia universalis). Hair loss can be permanent, or temporary.[7][1]
Alopecia areata is believed to be an autoimmune disease resulting from a breach in the immune privilege of the hair follicles.[12][13] Risk factors include a family history of the condition.[7] Among identical twins, if one is affected, the other has about a 50% chance of also being affected.[7] The underlying mechanism involves failure by the body to recognize its own cells, with subsequent immune-mediated destruction of the hair follicle.[7]
No cure for the condition is known.[7] Some treatments, particularly triamcinolone injections and 5% minoxidil topical creams,[11][10] are effective in speeding hair regrowth.[7][1]Sunscreen, head coverings to protect from cold and sun, and glasses, if the eyelashes are missing, are also recommended.[7] In more than 50% of cases of sudden-onset localized "patchy" disease, hair regrows within a year.[14][15][7] In patients with only one or two patches, this one-year recovery will occur in up to 80%.[16][17] However, many people will have more than one episode over the course of a lifetime.[15] In many patients, hair loss and regrowth occurs simultaneously over the course of several years.[7] Among those in whom all body hair is lost, fewer than 10% recover.[18]
About 0.15% of people are affected at any one time, and 2% of people are affected at some point in time.[7][18] Onset is usually in childhood.[7] Females are affected at higher rates than males.[9]
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^ abCite error: The named reference occurrence was invoked but never defined (see the help page).
^ abFreire P, Riera R, Martimbianco A, Petri V, Atallah AN (September 2019). "Minoxidil for patchy alopecia areata: systematic review and meta-analysis". Journal of the European Academy of Dermatology and Venereology. 33 (9): 1792–1799. doi:10.1111/jdv.15545. PMID30835901. S2CID73460786.
^ abYee BE, Tong Y, Goldenberg A, Hata T (April 2020). "Efficacy of different concentrations of intralesional triamcinolone acetonide for alopecia areata: A systematic review and meta-analysis". Journal of the American Academy of Dermatology. 82 (4): 1018–1021. doi:10.1016/j.jaad.2019.11.066. PMID31843657. S2CID209389315.
^Rajabi F, Drake L, Senna M, Rezaei N (2018). "Alopecia areata: A review of disease pathogenesis". British Journal of Dermatology. 179 (5): 1033–1048. doi:10.1111/bjd.16808. PMID29791718. S2CID43940520.
^Paggioli I, Moss J (December 2022). "Alopecia Areata: Case report and review of pathophysiology and treatment with Jak inhibitors". Journal of Autoimmunity. 133: 102926. doi:10.1016/j.jaut.2022.102926. PMID36335798. S2CID253320808.
^ abAlkhalifah A, Alsantali A, Wang E, McElwee KJ, Shapiro J (February 2010). "Alopecia areata update: part I. Clinical picture, histopathology, and pathogenesis". Journal of the American Academy of Dermatology. 62 (2): 177–88, quiz 189–90. doi:10.1016/j.jaad.2009.10.032. PMID20115945.