Alopecia Areata

Alopecia areata is a chronic inflammatory disease that causes non-scarring hair loss. Present evidence indicates that alopecia areata is caused by a T-cell–mediated autoimmune mechanism occurring in genetically predisposed individuals. The onset of alopecia areata may occur at any age. However, in most affected individuals the first episode occurs before the age of 40, with the peak age of onset between the 2nd and 4th decades. Dermoscopy can be helpful in confirming a diagnosis of alopecia areata. Alopecia areata may also involve the nails. Alopecia areata typically causes fine stippled pitting of the nails. Numerous studies have shown an increased risk of other autoimmune diseases in patients with alopecia areata. Atopic disease is also more common than expected in alopecia areata and is associated with earlier onset and more severe forms of hair loss. The importance of genetic factors in alopecia areata is apparent from the high frequency of a positive family history.