Clinical Features
Alopecia Areata affects men and women equally.
It can occur at any age but 60% of individuals lose their first patch of hair before the age of 20 years.
Hair loss is sudden and can occur in several different ways. Usually hair is lost
from the scalp in small coin-
Nail changes can occasionally be seen, usually as small pits in the nails often only visible with a magnifying lens.
Hair Loss:
Most individuals lose a circular patch of hair on any hair bearing area of the body but usually the scalp (img 1).
This patch is totally bald, smooth and not scarred and often shows the characteristic 'exclamation mark hairs'.
These are short broken off hairs, often seen at the edge of a patch and in the tapering shape of an exclamation mark. These are due to fragile hairs growing abnormally (in dystrophic anagen). A magnifying lens is often needed to identify these exclamation mark hairs to make a diagnosis of Alopecia Areata.
The hair loss is usually asymptomatic although some people may feel some tingling, burning or itching before the hair is lost.
Hair loss may occur at other body sites than the scalp or may be more extensive on the scalp.
The majority (70%) of affected individuals regrow their hair within a few months.
Sometimes the hair grows back white at first but this usually repigments (colours up again).
Others lose several patches of hair which can be recurrent.
Hair regrowth is less predictable and one in ten individuals progress to the chronic form
of Alopecia Areata with permanent and more extensive hair loss.
The hair loss may progress to involve the whole scalp (ALOPECIA TOTALIS) (img 2) or all the body hair (ALOPECIA UNIVERSALIS)
It is impossible to give an accurate prognosis in individuals with an isolated patch of Alopecia Areata.
Indicators of a poorer prognosis ( outlook) are atopy (that is, also having eczema, asthma or hayfever), family history of Alopecia Areata, early onset of hair loss, extensive hair loss, pattern of hair loss around the ears (ophiasis) and nail dystrophy.
Nail Changes:
Changes can be seen in one, some or all the nails.
Most commonly, fine irregular pitting is seen (img 3).
Other changes are longitudinal stripes or striations resulting in a sandpaper like appearance (trachyonychia); superficial splitting of the free edge of the nail (onychorrhexis) and horizontal grooves (Beau's lines).
