Chilblains (/ˈtʃɪlbleɪnz/; also known as pernio and perniosis) is a medical condition that occurs when a predisposed individual is exposed to cold and humidity, causing tissue damage. It is often confused with frostbite and trench foot. The cold exposure damages capillary beds in the skin, which in turn causes redness, itching, blisters, and inflammation. Chilblains can be prevented by keeping the feet and hands warm in cold weather. Chilblains can be idiopathic, but may also be a manifestation of a serious medical condition that needs to be investigated. A history of chilblains is suggestive of a connective tissue disease (such as lupus). 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.