The cause of this disease is probably an autoimmune reaction. This means that the immune system incorrectly attacks the body’s own cells. In the case of Alopecia Areata the cells that are attacked are in the hair follicles.
Genetic (hereditary) factors may also play a role. Almost 40% of people under age 30 with Alopecia Areata have at least one family member who has been diagnosed with the same disorder.
The risk of developing this disease is especially high in people who have asthma, allergic rhinitis, thyroid disease, vitiligo, pernicious anemia and down syndrome.