Alopecia areata is a hair loss condition that is characterized by the development of bald spots on the scalp or other areas of the body. This condition frequently begins with patchy hair loss from the scalp, and may occasionally progress to the whole scalp, called Alopecia totalis, or even to the entire body, called Alopecia universalis. The course of this condition is different for each individual, but it often tends to follow an unpredictable pattern with cycles of hair loss and regrowth.
The website of the National Alopecia Areata Foundation (NAAF) reports that approximately 4.7 million people are affected in the United States alone, suggesting that this is a relatively common disorder. Typically, the onset of alopecia areata first occurs during the years spanning early childhood to young adulthood, but it can be experienced in people of all ages. Alopecia areata is not a contagious condition, and it often occurs in otherwise healthy people, although it is sometimes associated with the occurrence of autoimmune disorders. Heredity may play a role in the development of this disorder because it is more likely to occur in people with affected relatives, and is somewhat more frequent in people with a family history of autoimmune diseases. Although this condition affects both genders, it is more common in females than in males.
Evidence suggests that alopecia areata is actually an autoimmune disorder — a condition in which the immune system launches a response against its own tissues — and that hair loss is due to immune cells attacking and damaging the hair follicles. In certain cases, hair loss may be directly associated with the immune response launched against an infected tooth. It is thought that some of the white blood cells that are mobilized by the body to fight a tooth infection may migrate to nearby hair follicles and mistakenly attack them, resulting in destruction of the follicles and subsequent hair loss. Alopecia areata that is associated with a tooth infection often occurs close to the site of the infection, such as at the hairline on the same side of the face as an infected molar. In many of these cases, effective treatment of the infection in the early stages can result in total reversal of hair loss.
Hair regrowth is often correlated with the extent of hair loss, and most patients that experienced mild and patchy hair loss will see regrowth within a few months to a year. Approximately 90 percent of patients will eventually regrow lost hair, but the remaining 10 percent of patients will experience either no regrowth or only slight regrowth. Several topical treatment options for alopecia areata have shown varying degrees of success, including topical steroids, stimulators of hair growth such as minoxidil, or synthetic irritants that may produce subsequent hair growth, such as anthralin. Monthly steroid injections or cortisone pills are other options, although cortisone pills are considered a less attractive alternative because they produce steroid side effects and hair loss usually resumes once the medication is stopped.