Alopecia areata is an autoimmune disease that targets the hair follicle.
It is characterized by sudden onset of patchy hair loss.
The diagnosis is clinical. Characteristic physical findings are exclamation point hairs (short, broken hairs tapering proximally at the scalp) and a positive pull test. A scalp biopsy shows perifollicular inflammation.
Topical or intralesional corticosteroids are appropriate for patients with limited hair loss. Skin atrophy can be a temporary side effect.
Alopecia areata (AA) is an autoimmune disease that causes inflammation of the hair follicles resulting in nonscarring hair loss, affecting scalp and body hair. Typically, one or more small round patch of hair loss without atrophy is noticed. This patchy hair loss may regrow spontaneously. In other cases there can be extensive patchy hair loss and in rare cases there is total body hair loss (alopecia areata universalis), or total scalp hair loss (alopecia totalis).
History and exam
Key diagnostic factors
- hair loss
- nonscarring alopecia
- exclamation point hairs
- normal underlying skin in bare areas
- nail pitting
Other diagnostic factors
- autoimmune disease
- family history of autoimmune disease
1st investigations to order
- clinical diagnosis
- positive hair pull test
Investigations to consider
- skin biopsy
limited hair loss (treatment desired)
limited hair loss (no treatment desired)
extensive hair loss (treatment desired)
extensive hair loss (no treatment desired)
- Tinea capitis
- Telogen effluvium
- British Association of Dermatologists' guidelines for the management of alopecia areata 2012
- Alopecia areata investigational assessment guidelines: part II
Alopecia areataMore Patient leaflets
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