Reduced incidence of skin cancer in patients with alopecia areata: A retrospective cohort study.

The risk of skin cancer in patients with alopecia areata (AA) is unknown. While the risk of skin cancer in chronic inflammatory alopecias may be elevated, AA shares many characteristics with vitiligo, an autoimmune illness associated with decreased risk of melanoma and non-melanoma skin cancers. In this retrospective cohort study, we determined the risk of developing skin cancer among patients with AA in a validated cohort relative to matched controls at two tertiary care hospitals in Massachusetts. There was a significantly decreased risk of NMSC in AA patients than controls (OR=0.63, 95% CI=0.48-0.81). There was a trend towards a protective effect of AA associated with melanoma (OR=0.65, 95% CI=0.39-1.09). There was no difference in anatomic distribution of skin cancer between patients with AA and controls. Our study demonstrates a decreased risk of nonmelanoma skin cancer and a trend towards reduced risk of melanoma in patients with AA.