Alopecia Areata Update

The document from February 1, 2010, summarizes research on Alopecia Areata (AA), an autoimmune disease causing nonscarring hair loss with a prevalence of 0.1% to 0.2% in the U.S. It describes AA's clinical presentation, including well-demarcated patches of hair loss, and notes that up to 50% of patients may recover within a year without treatment, though the prognosis is generally unpredictable. Poor prognostic factors include extensive hair loss, certain patterns, long duration, atopy, family history, and young age at onset. The pathogenesis of AA involves immune-mediated targeting of hair follicles, with genetic susceptibility linked to HLA class II alleles and environmental factors like stress potentially playing a role. The document also discusses the use of animal models in research and the need for further study to understand AA's mechanisms and develop effective treatments.