Alopecia areata (AA) is an autoimmune disorder characterized by non-scarring hair loss of the scalp or any hair-bearing surface.
Alopecia areata affects approximately 2% of the general population. AA has a significant influence on patients' quality of life and may induce psychological disorders.
In AA, CD4+ and CD8+ T-cells violate the immune privilege of the anagen hair follicle, leading to loss of the growing hair shaft. A genome-wide association study demonstrated a genetic predisposition to AA . Additionally, environmental insults, such as viral infections, trauma, or psychosocial stress, have also been suspected to possibly contribute to the development of the disease .
The clinical manifestations of AA vary from small well-defined patches of hair loss to the diffuse involvement of the scalp or the entire body. The majority of AA patients experience unpredictable relapsing and remitting episodes. In a number of patients, it can be persistent, especially when the hair loss is extensive.