Alopecia areata

Alopecia areata is a relatively common condition which may occur at any age in either sex. The prevalence of Alopecia areata globally is around one in a thousand people (1). It can affect all ages, but the prevalence appears higher in children compared to adults and a greater incidence has been reported in females than males, especially in patients with late-onset disease, defined as age greater than 50 years. (2) It is a non-scarring condition which can affect the hair follicles and the nails.

Indicators of a poor prognosis are the presence of other immune diseases, family history, young age at onset, nail dystrophy, extensive hair loss, and hair loss at the inferior hair line of the scalp. (3)

Alopecia areata can be categorized according to extent or pattern of hair loss (2)

• Patchy - most common presentation with limited hair loss
• Extensive - over 50% hair loss
• Alopecia totalis - total loss of hair on the scalp
• Alopecia universalis - total loss of body hair
• Diffuse hair loss - can be seen occasionally

The cause is thought to be an autoimmune phenomenon as often; there is a co-existing autoimmune disease e.g. pernicious anaemia, thyroid disorders, vitiligo, diabetes.

There are lymphocytic infiltrates around the follicles and a high prevalence of autoantibodies and abnormalities on the titres of circulating T lymphocytes (2).

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Reference:

1. Villasante Fricke AC, Miteva M. Epidemiology and burden of alopecia areata: a systematic review. Clin Cosmet Investig Dermatol. 2015;8:397-403.

2. Sibbald C. Alopecia Areata: An Updated Review for 2023. J Cutan Med Surg. 2023 May-Jun; 27(3): 241–259.

3. Cranwell WC, Lai VW, Photiou L, et al. Treatment of alopecia areata: An Australian expert consensus statement. Australas J Dermatol. 2019 May;60(2):163-170.