There are many reasons for hair loss. One of the most common causes is alopecia areata, in which hair disappears in circles on the scalp.
In some cases, hair loss is scattered. In other cases, it can cause total baldness. As hair begins to regrow, new circles of hair loss may appear in other areas.
The cause of alopecia areata is probably an autoimmune reaction. Immune cells of the body seem to attack hair follicles, leading to hair loss. No one knows why immune cells make this mistake, but genetics may play a role.
There is no cure for alopecia areata, but there are ways to encourage hair growth. Cortisone cream applied to the areas with no hair can sometimes stimulate hair growth. In cased of severe hair loss, injections of cortisone can be effective. The drug anthralin (Drithocreme, Dritho-Scalp, Micanol) produces mild irritation of the scalp. This can stimulate mild hair growth.
With alopecia areata, hair usually grows back within a year. Because there are other causes of hair loss, and because alopecia areata can differ widely in extent and appearance, it is important to see a doctor for the correct diagnosis and treatment.