Alopecia areata in patients with inflammatory bowel disease: an overview.

Alopecia areata (AA) is one of the most common causes of non-scarring hair loss, which is associated with the premature induction of hair follicle regression. The pathogenesis of AA is unknown, although it is believed that a complicated autoimmune mechanism with Th1 lymphocytes and proinfammatory cytokines, such as IFN-γ, TNF-α, IL-1 and IL-2, may be involved. AA may occur as a single disease entity or coexist with other autoimmunological disorders. In some cases the relationship with infammatory bowel disease (IBD) was observed and the link between molecular pathways and main proinfammatory cytokines in IBD and AA has been suggested. AA is also described in literature as a side efect of biological therapy with the anti-TNF-α agents. To address the association between AA and IBD, in this review we discuss the most relevant clinical studies and case reports found in MEDLINE, Pubmed and EMBASE.