Frostbite degree: (1) 1 degree: injury and epidermis layer, local congestion, redness and swelling, the formation of erythema, can be self-healing, 5-10 days with skin peeling off. (2) 2 degrees: injury and skin hair layer, blister formation, can recover on its own, longer, 2-3 weeks blisters disappear, the formation of scabs, 3-4 weeks scabs off healing. (3) Degree 3: Injury and skin and subcutaneous tissue, skin necrosis of the whole layer, blue-purple, long and unbearable pain, up to 3 to 5 weeks, edema is slow to subside. The necrotic tissues dry out and form black dry scabs, and the scabs separate and fall off to reveal granulation tissue. (4) Degree 4: skin, subcutaneous, muscle and bone are necrotic, mainly for limb pain, lasting 15-30 days, until the formation of dry necrosis, pain disappears. Some patients still have pain after amputation and may have combined neuritis, arteritis, and infection. The 4th degree frostbite demarcation line appears 12 days after rewarming, and the dry limb is shed for as long as 2 months. First aid and treatment of frostbite: (1) Remove from the environment, rewarm as quickly as possible, and apply frostbite cream after rewarming. (2) Give systemic symptomatic support treatment, pain relief, satiation, cardiac strengthening, prevention of renal failure, shock. (3) Frostbite is divided into two phases: the freezing phase and after melting. (4) Rapid rewarming: water temperature 42 to 45 degrees, usually about 20 minutes, severe pain during rewarming, you can use drugs until the frozen tissue is softened and the skin is flushed. (5) Treatment after melting: local exposure, poor microcirculation at the frostbite site, easy to use topical drugs locally, local drugs are mainly: frostbite cream containing furacilin, dexamethasone. Give antibiotics, topical furacilin solution wet dressing, 2/day. 4 degrees try to wait for frostbite tissue to fall off on its own, before surgery must wait until after the demarcation line is obvious. (5) Frostbite combined with shock treatment: rehydration, improve microcirculation, avoid the use of vasoconstrictive drugs. (6) 4th degree inpatient treatment: room temperature 25 degrees, no smoking, high-calorie diet, bed rest. (7) Systemic medication for severe frostbite: can improve microcirculation. Low right 500ml 1/day IV Vitamin E 20mg 3/day orally Vitamin C 1g 3/day orally Rutin 20mg 3/day orally (8) Injection of tetanus for frostbite above degree 2.