What is alopecia areata?
Alopecia is a general term for hair loss. Alopecia areata is a specific, common cause of hair loss that can occur at any age. It usually causes small, coin-sized, round patches of baldness on the scalp, although hair elsewhere such as the beard, eyebrows, eyelashes, body and limbs can be affected. Occasionally it can involve the whole scalp (alopecia totalis) or even the entire body and scalp (alopecia universalis). It is not possible to predict how much hair will be lost. Regrowth of hair in typical alopecia areata is usual over a period of months or sometimes years, but cannot be guaranteed. The hair sometimes regrows white, at least in the first instance. Further hair loss is not uncommon. In alopecia totalis and alopecia universalis, the likelihood of total regrowth is less.
What causes alopecia areata?
Hair is lost because it is rejected by the affected person’s immune system which does not recognise the hair roots (follicles) as "self", but regards them as "foreign" (autoimmunity). Why this happens is not fully understood, nor is it known why only localised areas are affected and why the hair regrows again.
Someone with alopecia areata is more likely than a person without it to develop other autoimmune conditions such as thyroid disease, diabetes and vitiligo (white patches on the skin), although the risk of getting these disorders is still low. Your doctor may suggest a blood test looking for antibodies that may predict whether you are likely to develop thyroid problems or pernicious anaemia.
Alopecia areata is not catching nor is it related to diet or vitamin deficiencies. Stress, particularly events such as bereavement, separation and accidents, occasionally appears to be a trigger for alopecia areata.
Is alopecia areata hereditary?
There is a genetic predisposition to alopecia areata and close family members may be affected. Thyroid problems or diabetes are also more common.
What are the symptoms?
There may be a tingling sensation in the scalp. It can be a very upsetting condition to the sufferer, especially if the bald area cannot be disguised by hairstyle.
What does alopecia areata look like?
Typically, it starts as one or more bald, smooth patches on the scalp, which are not inflamed or scaly. It tends to affect the pigmented hair so there may be some white hairs left within the bald area in older people. Sometimes the hair loss is diffuse rather than well-circumscribed patches. Short, tapered hairs, known as exclamation mark hairs that are characteristic of alopecia areata, may be seen at the edge of the bald patch. Regrowth usually starts at the centre of the bald patch with fine white hair that thickens with time and usually regains its colour. Some people with alopecia areata develop small pits on their nails, similar to the dimples seen on a thimble.
Can it be cured?
No, alopecia areata cannot be cured. If the hair loss is patchy, there is a good chance (about 60-80%) that there will be complete regrowth within 1 year without treatment. There may, however, be further episodes of hair loss in the future. If there is very extensive hair loss from the start, the chances of it regrowing may not be as good. In people with Down's syndrome, or those who have severe eczema, the chances of regrowth are not so good either.
To find out about available treatments for Alopecia Areata please go to this page on the website of the British Association of Dermatologists