A review of immunologic factors involved in alopecia areata and the effects of diphencyprone on these factors

Alopecia areata (AA) is a sudden non-scarring hair loss that can be seen in any hairy area in the form of round or oval patches. It is an autoimmune disorder with an immunological response against hair follicles that is caused by genetic and environmental factors. The prevalence of AA is about 0.1% to 0.2% worldwide. Depending on the severity of the disease and sites of involvement, it can be divided into: Alopecia with Patchy pattern, alopecia reticularis, alopecia totalis, alopecia universalis, alopecia ophiasis, alopecia sisiapho, diffuse type and perinevoid alopecia areata. There are various treatment options for AA, but once terminated, they have a high recurrence rate. AA is known for the infiltration of T lymphocytes around the hair follicle bulb, and corticosteroids are its main treatment. Another treatment is topical immunotherapy, the most important of which is Diphenylcyclopropenone (DPCP). It is used in cases that have more than 50% hair loss or are resistant to treatment. The exact DPCP mechanism of action is not well understood, but it may have some kind of antigenic competition and reduce the production of anti-hair follicle antibodies. It can alter the immune response in the skin and alter the ratio of CD4 to CD8 cells around the hair follicle in a way that enhances healing of the disease. It is stated that the rate of hair regrowth in DPCP treatment is about 50% on average. In this article, we review the latest findings of about AA and discuss its therapeutic aspects, especially with DPCP.