Alopecia Areata: Small Bald Spots on the Scalp

It comes as a shock when round bald patches appear for no apparent reason on someone’s previously thick head of hair. The condition, whose onset is usually sudden, is called alopecia areata (AA).

Alopecia areata is an inflammatory hair loss condition currently thought to be an autoimmune disorder. Its characteristic appearance makes a diagnosis quite simple. The circular bald spots are generally between two and six centimetres in diameter and have clear borders.

Progression of the condition varies greatly, starting with the number and size of the bald spots. Some people have only one or two small spots, others have many that continue to spread. In rare instances it leads to total hair loss.

Regardless of its extent, AA is neither painful nor — as would be the case in eczema of the scalp — itchy. But the emotional toll that it takes, particularly in women, can be enormous. It’s very hard to cope with the loss of your hair. You feel unattractive and, unfortunately, you also get negative reactions from other people.

A person’s risk of developing AA at some time is about one in 50. Unlike many other hair loss conditions, it’s reversible — the hair can grow back. This is because AA does not destroy the roots of hair follicles, but only causes local inflammation that disrupts the growth of hairs and makes them fall out.

The probable cause is an abnormal immune reaction that often corrects itself. In more than half of the cases, in fact, there is spontaneous healing within a year. Later, too, the hairs can begin to sprout again at any time, be it on their own or through treatment. But in some cases, unfortunately, the hair could fall out again.

What exactly causes the condition is still unknown. Many factors could play a role, sometimes in combination, including heavy stress, allergies and the presence of a thyroid or autoimmune disorder. A genetic predisposition is certain because alopecia areata runs in families. Specific therapies could be devised if the genes responsible are identified.

Until AA’s cause has been pinpointed, only nonspecific therapy is possible. Common treatments involve application of a lotion to the affected areas, injection of a corticosteroid under the skin surface and a phototherapy called PUVA (psoralen + ultraviolet A radiation). The use of corticosteroids is controversial.

Immune therapy with the chemical diphenylcyclopropenone (DCP) has the highest success rate. When applied regularly for an extended period, it triggers an allergic reaction and could cause immune cells to stop their misguided ‘anti-hair defence’.