Alopecia areata is manifested as the loss of hair in well-circumscribed patches of normal-appearing skin, most commonly on the scalp and in the region of the beard. The onset is typically rapid, and the disease can progress to the point where all the hair is lost on the scalp (alopecia areata totalis) or even on the whole body (alopecia areata universalis).
Diagnostic Criteria for Alopecia Areata.
|Diagnostic Tool||Diagnostic Findings|
|Family history||Atopy, thyroid disease, or other autoimmune disorders may be associated with alopecia areata; a family history of any of these disorders may therefore be diagnostic|
|Hair and skin||Most characteristic diagnostic finding is the presence of circumscribed, hairless patches or large alopecic areas in otherwise normal-appearing skin areas; pigmented hair is preferentially attacked and lost in active disease, whereas regrowth is frequently characterized by tufts of white hair; sudden pseudowhitening of hair is observed in a rare, rapidly progressing, diffuse variant form of alopecia areata|
|Nails||Nail changes, if present, are usually characterized by pitting; onychodystrophy is less common|
|Eyes||Ocular abnormalities include lens opacities and abnormalities of retinal pigment epithelium|
|Dermoscopy||Yellow dots (i.e., keratotic plugs in follicular ostia) are often seen in alopecia areata but are not specific for the diagnosis|
|Cadaver hairs||Comedo-like cadaver hairs (black dots) may also be present|
|Exclamation-mark hair||Distal segment of the hair shaft is broader than its proximal end, resembling an exclamation mark|
|Follicular ostia||Openings in the hair follicles through which the hair fiber emerges from the skin; these ostia are well preserved in alopecia areata, in contrast to the findings in scarring alopecia|
|Pull test*||A positive pull test at the margins of alopecic lesions that produces telogen (“club”) or dystrophic anagen hairs supports a clinical working diagnosis|
|Laboratory tests||None of the available tests will confirm the diagnosis, but thyroid-function tests and tests for thyroid antibodies may be advisable because of the increased association between alopecia areata and thyroid autoimmunity; abnormal results of thyroid-function tests, the presence of thyroid autoantibodies, or both further support a clinical or histologic working diagnosis of alopecia areata|
|Histologic examination†||Biopsy specimens should be obtained only if the clinical diagnosis is in doubt; on histologic examination, a dense, peribulbar lymphocytic infiltrate is seen in acute alopecia areata|
* The pull test is also positive in other conditions, such as fungal hair infections.
† This perifollicular infiltrate can be deceptively subtle in long-standing, chronic disease.
- Gilhar A, Etzioni A, Paus R. Alopecia areata. N Engl J Med. 2012 Apr 19;366(16):1515-25. [Medline]
- Alkhalifah A, Alsantali A, Wang E, McElwee KJ, Shapiro J. Alopecia areata update: part I. Clinical picture, histopathology, and pathogenesis. Am Acad Dermatol. 2010 Feb;62(2):177-88, quiz 189-90. [Medline]
- Alkhalifah A, Alsantali A, Wang E, McElwee KJ, Shapiro J. Alopecia areata update: part II. Treatment.
J Am Acad Dermatol. 2010 Feb;62(2):191-202. [Medline]
Created Jun 14, 2012.