Chilblains (/ˈtʃɪlbleɪnz/; also known as pernio and perniosis) is a medical condition that is often confused with frostbite and trench foot. Chilblains are a tissue injury that occurs when a predisposed individual is exposed to cold and humidity. The cold exposure damages capillary beds in the skin, which in turn can cause redness, itching, blisters, and inflammation. Chilblains can be prevented by keeping the feet and hands warm in cold weather. The underlying cause of chilblains can be idiopathic in origin but may also be manifestations of serious medical conditions that need to be investigated. A history of chilblains is suggestive of a connective tissue disease. Chilblains in infants, together with severe neurologic disease and unexplained fevers, can be seen in Aicardi–Goutières syndrome, a rare inherited condition.
^Rustin, M.H.A.; Newton, Julia A.; Smith, N.P.; Dowd, Pauline M. (2006). "The treatment of chilblains with nifedipine: the results of a pilot study, a double-blind placebo-controlled randomized study and a long-term open trial". British Journal of Dermatology120 (2): 267–75. doi:10.1111/j.1365-2133.1989.tb07792.x. PMID2647123.