[Alopecia areata].

Alopecia areata. Alopecia areata is a common T-cell mediated autoimmune disease affecting hair and nails. It is a non-scarring form of alopecia, commonly patchy, but it may cover the whole scalp and even body hair. Appearing on genetically predisposed people, it evolves in variable and often unpredictable ways throughout life, in episode whose triggering causes remain unknown. Its psychological impact is often large. The therapeutic management takes into account the patient's request, after a simple explanation about the disease and its treatment. Although it is challenging, some significant improvements of our knowledge concerning physiopathology and the treatment of alopecia areata have emerged in recent years.