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Alopecia areata

This page aims to give you a general overview of hair disorders.

Alopecia areata is a form of alopecia that is still poorly understood. It manifests itself as the rapid appearance of round patches that are completely devoid of hair. It is more common than one might imagine (1% of the population are affected), and can strike both women and men, often well before the age of 20.

Sudden and localised hair loss

Alopecia areata manifests itself as the sudden loss of all hair on one or several parts of the scalp. Circular patches of smooth skin then appear, measuring several centimetres in diameter and often located around the back of the head (above the nape of the neck and around the ears). The patches can become progressively larger, eventually forming large hairless areas. Around them, an area with very short hair (1 to 2 cm) that is abnormally thin towards the roots is apparent.
Alopecia areata can sometimes affect other parts of the body: hairless patches can form in the beard or eyebrow area, or on any hairy part of the body.
In the vast majority of cases (95%), alopecia areata only affects a few patches or hair or body hair. However, in some rare cases it can affect the entire scalp (we call this alopecia “totalis”) or the entire body (alopecia “universalis”).
Alopecia areata affects both men and women, but young individuals and those with brown hair are the most commonly affected.

As yet poorly identified origins

The causes of alopecia areata are still poorly understood. The condition would seem to be due to an autoimmune inflammatory disease: for some unidentified reason, the immune system brutally attacks the hair follicles and stops their activity, without actually destroying them. That’s right, whereas in other forms of alopecia the scalp becomes smooth, in alopecia areata the hair orifices remain present: the hair follicles lie dormant but are ready to resume their activity.
Stress seems to also play a major role in alopecia areata: often, the individuals affected have suffered a severe emotional shock in the preceding weeks or months (bereavement, divorce, intense fear, radical change in lifestyle, etc.).
Lastly, alopecia areata can be hereditary: 20% of individuals suffering from alopecia areata have relatives who are also affected.

Variable progression

In most cases, alopecia areata heals spontaneously and the hair returns after several months, even in the absence of treatment. It often grows back as fine white down at first, then it gradually thickens and regains its colour.
Nevertheless, in the most severe cases (alopecia totalis or universalis), the prognosis is less optimistic and hair can have trouble growing back or recovering its former density.
Moreover, alopecia areata is often recurring: half of the individuals affected experience relapses, sometimes several years after the first bout.
To optimise the chances of regaining a dense head of hair and reduce the risk of relapses, see a skin specialist as soon you notice a patch of alopecia areata: different locally-applied or oral treatments can curb the autoimmune response responsible for the alopecia areata and stimulate new hair growth.