冻疮是身体表面受到低温伤害后局部血液循环发生障碍而产生的病变。

一般由于天气寒冷引起的局限性炎症损害，为冬天的常见疾病，不具传染性。

通常出现在肢体的末梢和暴露的部位，如手、足、鼻尖、耳边、耳垂和面颊部等部位。表现为局限淤血性紫红色水肿性斑块，按压之色褪，去压后缓慢恢复红色。皮肤出现局限性瘙痒、水肿、红斑，严重可能出现水疱、糜烂和溃疡。冻疮一旦出现，要等天气转暖后才会逐渐愈合。

中医上认为多因身体虚弱，外感寒邪，则经络受阻、气血凝滞而成。初起皮肤呈苍白漫肿、麻木冷感，解冻复温后呈青紫色，斑块、水泡、肿胀等，并伴有灼痛、瘙痒。重度冻疮愈合后将有瘢痕形成。

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. Damage to capillary beds in the skin causes redness, itching, inflammation, and sometimes blisters. Chilblains can be reduced by keeping the feet and hands warm in cold weather, and avoiding extreme temperature changes. Chilblains can be idiopathic (spontaneous and unrelated to another disease), but may also be a manifestation of another 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.