Acrocyanosis: the Flying Dutchman.

Acrocyanosis is symmetric, painless, discoloration of different shades of blue in the distal parts of the body that is marked by symmetry, relative persistence of the skin color changes with aggravation by cold exposure, and frequent association with local hyperhidrosis of hands and feet. Described over a century ago and despite seeming familiarity, it remains a poorly understood condition that shares much in clinical presentation with other conditions characterized by skin color changes in the distal parts of the body. The diagnosis remains mostly clinical, and pathological mechanisms vary suggesting that acrocyanosis may not be a single entity. We performed an extensive literature review to summarize existing knowledge about the demographics, pathology, diagnosis, and treatment of this condition.