There are many skin diseases caused by cold, and the common ones in clinical practice are frostbite, frostbite, cold erythema multiforme, cold lipofuscinosis, cold hypersensitivity dermatosis, Raynaud’s disease, extremity cyanosis and a series of other skin diseases. 1. frostbite: bruised, inflammatory skin disease at the ends of the body’s extremities and exposed areas due to cold and humidity, with lesions often appearing as erythema or nodules and, in severe cases, blisters and ulcers, and patients Patients can feel itchy, swollen or painful, and in severe cases even cause systemic symptoms; 2, frostbite: injury caused by local tissue freezing due to short exposure of the limbs to extremely low temperatures or longer exposure to below 0 ℃, divided into two categories of systemic and localized injuries. Systemic injury includes frostbite and frostbite, local injury includes frostbite, frostbite, etc.; 3, cold erythema multiforme: acute self-limiting inflammatory skin disease involving skin and mucous membrane with erythema, papules and blisters as the main manifestation. The main clinical symptoms include skin and mucous membrane damage, round erythema, fever, malaise, muscle and joint pain, which may lead to complications of pneumonia, gastrointestinal bleeding, myocarditis, infectious shock, and corneal perforation. Cold and humid climate may induce catarrh, which is related to cold leading to skin vasoconstriction; 4. Cold lipofuscinosis: It is an inflammation caused by cold leading to limited damage to local subcutaneous fatty tissue. Patients may have subcutaneous nodules or plaques with clear borders and reduced surface temperature, which may be cyanotic or greenish-red. The patient may have well-defined subcutaneous nodules or plaques with reduced surface temperature, which may be cyanotic or cyanotic. The patient should pay attention to good protection and keep warm when the weather changes; 5. Cold hypersensitivity dermatosis: it can occur in cold environment, where skin damage often occurs in exposed areas, manifesting as ulcers, necrotic plaques, pemphigus, purpura, hard erythema and many other damages. It can be treated with antihistamines, corticosteroids, etc. Usually pay attention to cold prevention and warmth; 6. Raynaud’s disease: after cold or emotional stress, paroxysmal small arteries of the extremities can appear strongly contracted, causing ischemia of the extremities. The skin color of the extremity can change from pale to cyanotic and then to flushed during the attack of this disease, so it is necessary to avoid cold stimulation and emotional excitement; 7, extremity cyanosis: the symptoms are obvious after cold, mainly in the extremities and fingers, especially in the hands, the skin of the fingers and palms is cold and cyanotic. The local skin is cold, the skin temperature is lowered, and the palm often has hyperhidrosis, etc.