A 15-year-old girl presents with patches of hair loss on her scalp that have been present for the last 6 months. She reports that her scalp is not itchy or painful and denies any recent illnesses, diet changes, or stressful life events. She does not have any other medical conditions and takes no medications. Her uncle had a similar condition that started when he was in his 20s, but no one else in the family has experienced hair loss. The patient says she has not tried any treatments for the condition. On examination, she has several well-demarcated patches of hair loss on her frontal and parietal scalp, with no perifollicular erythema or scale.
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Alopecia areata (AA) is a sudden-onset autoimmune condition characterized by discrete areas of nonscarring hair loss.1 The extent of alopecia can range from a few patches of hair loss to complete loss of all scalp hair (alopecia totalis) or all body hair (alopecia universalis).1
The earliest known records of AA are found in ancient Egyptian papyruses dating back to 1500 BC. In these texts, a phrase that translates to “bite alopecia” is thought to describe patchy AA.2 The term alopecia was first mentioned by Hippocrates in approximately 400 BC; later Celsus (25 BC-50 AD) first described “areas of alopecia” in his medical writings.2 In these documents, Celsus used the term alopekia to describe bald spots in the scalp and beard. AA also has been referred to as porrigo decalvans, tinea decalvans, and phytoalopecia.2
In the United States, the lifetime prevalence of AA is estimated to be 2.5%.3,4 Disease onset may occur at any age, including early childhood, and both sexes are affected equally.5 The majority of cases develop before 40 years of age.4
Alopecia areata is thought to be caused by the breakdown of immune privilege (IP) in the hair follicle (HF) and the subsequent development of autoimmunity against the HF.6 Immune privilege refers to the ability of certain organs to evade potential harm from an inflammatory immune response.6 Normally, HFs produce a milieu of local factors that maintain their IP, but in patients with AA, this process breaks down.1 The underlying cause of AA remains unknown; it is hypothesized that susceptible patients may have defects in the HF or dysregulation of their immune system.6
Risk factors for AA include genetic susceptibility, concurrent autoimmune disease, and environmental factors.7 Individuals with a family history of AA are more likely to develop AA, but onset and severity are difficult to predict.6,7 Genome-wide association studies have identified numerous genetic loci associated with increased AA risk, especially in the human leukocyte antigen region.1,7 Alopecia areata is associated with other autoimmune diseases, such as vitiligo, inflammatory bowel disease, psoriasis, thyroid disease, rheumatoid arthritis, and systemic lupus erythematosus.1 In patients with a genetic predisposition, possible environmental triggers include emotional stress, physical injury, viral infection, drugs, and vaccinations; however, in the majority of cases, the precipitating factor cannot be identified.1
In addition to its genetic variability, AA also demonstrates phenotypic variability. Alopecia areata classically manifests as well-circumscribed round, hairless patches without perifollicular scaling or erythema, but other distinctive patterns may be observed.1 For instance, ophiasis denotes a band-like pattern of hair loss along the occipital and temporal margins, and sisaipho denotes the opposite, that is, extensive hair loss sparing the margins.1 As AA may affect any hair-bearing site, hair loss may occur in the beard area and may involve the eyebrows and eyelashes.1 It may target pigmented hairs and spare white hairs, or it may induce diffuse hair loss without discrete patches.1 In some patients, the disease may progress to alopecia totalis or alopecia universalis. Nail changes, such as pitting or trachyonychia, are associated with severe manifestations of AA.1
In AA, exclamation point hairs, a specific finding defined by proximal narrowing of the hair shaft, may be appreciated on dermoscopy in addition to nonspecific yellow dots, black dots, and dystrophic hairs.1 Although AA usually is clinically diagnosed, a skin biopsy may be performed if the diagnosis is uncertain.
Histopathology will show characteristic peribulbar and intrabulbar lymphocytic infiltrate. The infiltrate also may contain eosinophils, CD1+ cells, and CD8+ cells. Other histologic findings may include pigment incontinence and an increased number of miniaturized hair follicles.1
Depending on examination findings, the clinician may consider other causes of nonscarring alopecia in the differential diagnosis, such as tinea capitis, androgenetic alopecia, telogen effluvium, and trichotillomania. In contrast to AA, tinea capitis presents with pruritus, erythema, and scaling of the scalp.1 In patients with androgenetic alopecia, diffuse hair loss occurs in a sex-specific pattern, and in patients with trichotillomania, patches of hair loss are irregular in shape and contain broken hairs.1 Telogen effluvium presents as diffuse hair shedding as opposed to the discrete patches of hair loss seen in AA.1
There is no cure for AA and treatment options have variable efficacy.8 Patients may recover spontaneously but most treated patients experience relapse.1 For patients with patchy disease, intralesional corticosteroids administered over multiple sessions are preferred; for those with limited disease, topical corticosteroids alone may be beneficial. However, for patients with extensive or rapidly progressive disease, systemic corticosteroids may need to be considered, bearing in mind potential side effects. Topical options for AA include minoxidil, anthralin, and immunotherapy (eg, diphenylcyclopropenone).1,8 Promising results have been reported with novel targeted approaches, such as Janus kinase inhibitors that block the downstream signaling pathway of interferon-γ.8
With any of these treatment approaches, patient education and counseling are necessary to manage patient expectations. Given its unpredictability and cosmetic consequences, AA can be a devastating diagnosis that negatively affects quality of life. Psychological comorbidities include depression and anxiety, and patients may require professional support as they cope with the disease.1
The patient in this case was diagnosed with AA clinically and she was immediately started on corticosteroid injections, after which she experienced some hair regrowth. However, several months later she started developing new patches of hair loss for which she is undergoing additional corticosteroid injections.
Tiffaney Tran, BS, is a medical student at Baylor College of Medicine, in Houston, Texas; Tara L. Braun, MD, is a resident in the Department of Dermatology at Baylor College of Medicine; and Christopher Rizk, MD, is a dermatologist affiliated with Baylor College of Medicine.
1. Pratt CH, King LE, Messenger AG, Christiano AM, Sundberg JP. Alopecia areata. Nat Rev Dis Primers. 2017;3:17011. doi:10.1038/nrdp.2017.11
2. Broadley D, McElwee KJ. A “hair-raising” history of alopecia areata. Exp Dermatol. 2019;29(3):208-222. doi:10.1111/exd.14073
3. Safavi K. Prevalence of alopecia areata in the First National Health and Nutrition Examination Survey. Arch Dermatol. 1992;128(5):702. doi:10.1001/archderm.1992.01680150136027
4. Mirzoyev SA, Shrum AG, Davis MDP, Torgerson RR. Lifetime incidence risk of alopecia areata estimated at 2.1% by Rochester Epidemiology Project, 1990-2009. J Invest Dermatol. 2014;134(4):1141-1142. doi:10.1038/jid.2013.464
5. Fricke ACV, Miteva M. Epidemiology and burden of alopecia areata: a systematic review. Clin Cosmet Investig Dermatol. 2015;8:397-403. doi:10.2147/CCID.S53985
Rajabi F, Drake LA, Senna MM, Rezaei N. Alopecia areata: a review of disease pathogenesis. Br J Dermatol. 2018;179(5):1033-1048. doi:10.1111/bjd.16808
6. Simakou T, Butcher JP, Reid S, Henriquez FL. Alopecia areata: a multifactorial autoimmune condition. J Autoimmun. 2019:98:74-85. doi:10.1016/j.jaut.2018.12.001
7. Renert-Yuval Y, Guttman-Yassky E. The changing landscape of alopecia areata: the therapeutic paradigm. Adv Ther. 2017;34(7):1594-1609. doi:10.1007/s12325-017-0542-7
8. Renert-Yuval Y, Guttman-Yassky E. The changing landscape of alopecia areata: the therapeutic paradigm. Adv Ther. 2017;34(7):1594-1609.