Alopecia areata

Published on 05/03/2015 by admin

Filed under Dermatology

Last modified 22/04/2025

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Alopecia areata

DDx Ref       5380152

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Localized alopecia areata: round, discrete patches of hair loss. The scalp is smooth without scaling, erythema, or scarring.

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Alopecia areata in the beard skin can be subtle and noted only as adjacent shaved hairs regrow. Affected beard area skin is smooth; the round patch is hairless without inflammation.

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Alopecia areata of the occiput. This large hairless patch is characteristically round and devoid of hair.

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Alopecia areata can affect any site of hair-bearing skin. Here, it has resulted in loss of eyelash hairs.

DESCRIPTION

A non-scarring hair loss. Typically rapid onset in sharply defined, usually round or oval area. Loss may be diffuse or focal, or band-like at scalp margins.

HISTORY

• Most common in children and young adults. • Sudden hair loss in areas that are sharply demarcated, 1–4 cm. • Eyelashes and beard may be involved, and (rarely) other parts of the body. • Total hair loss of the scalp (alopecia totalis) is most frequent in young people; may be accompanied by cycles of growth and loss. • Total hair loss of the body (alopecia universalis) is very rare. • Regrowth in 1–3 months; may be followed by loss in other areas. • Prognosis for total regrowth, if limited involvement, is good.

PHYSICAL FINDINGS

• Most common pattern: patchy. Other patterns: ophiasis (band-like loss at scalp margins) and ophiasis inversus (spares scalp periphery, involves crown). Diffuse pattern least common. • Skin typically very smooth but may have short hair stubs. • Tapered hairs resembling exclamation points best seen at margin of circular loss. • New regrowth may be fine and white. • Diffuse fine nail pitting in up to 30%. • Biopsy if the clinical presentation not typical. Findings include peribulbar lymphocytes, miniaturized follicles, telogen to vellus hair ratio of 1.5 : 1, and increased telogen and catagen follicles. • May be associated, but not caused by with thyroid disease, pernicious anemia, Addison disease, vitiligo, lupus erythematosus, ulcerative colitis, diabetes mellitus, Down syndrome. • Differential diagnosis: trichotillomania, tinea capitus, syphilis, telogen effluvium, diffuse androgenetic alopecia.