What is the cause of frostbite? Is there any way to prevent it?

Frostbite occurs in the cold season, generally below 5℃. It heals itself after the climate warms in spring, but it is easy to recur after winter. Once many people get frostbite, it will recur every winter. Frostbite is the most common among children and pupils. Hands, feet and auricles are most likely to occur. Symptoms include local skin cooling, dark purple-red or purple-blue patches, and soft pressing. In severe cases, blisters will appear, which will form erosion or ulcer after rupture. I feel itchy and burning after encountering heat. Delayed healing has induration. Severe frostbite will leave scars, and the mechanism of frostbite allergy to cold is not very clear, which may be related to skin and blood vessels allergy to cold, autonomic nerve dysfunction and genetic factors. People who often come into contact with cold water are prone to this disease. People who live in some coastal areas in the north and south of China or in cold and humid environments for a long time are prone to this disease. Humidity can accelerate the heat dissipation of body surface, so the incidence of chilblain is higher in areas with high humidity in winter. In addition, autonomic nerve dysfunction, poor blood circulation in limbs, sweating in hands and feet, lack of exercise, malnutrition, anemia and some chronic diseases are often the causes of chilblain. Prevention of frostbite is mainly: keep warm and dry, shoes and socks should not be too tight, frostbitten parts should not be baked immediately and soaked in hot water. Vaseline or other oils can be applied to vulnerable parts to protect the skin. Unforgetted chilblain can be topically rubbed with drugs that promote blood circulation, such as 10% camphor essence or pepper tincture. Pepper water has a certain effect on local scald. When ulcer occurs, apply 5% boric acid ointment, monascus toxin ointment or lard honey ointment (lard 30% honey 70%) for dressing. At the same time, oral peripheral vasodilators such as nicotinic acid. The treatment principle of traditional Chinese medicine is to warm meridians and dredge collaterals, promote blood circulation and remove blood stasis, and the prescription is modified by Danggui Sini Decoction or Yanghe Decoction. The key to cure chilblain is to get rid of wet and cold environment and cold and warm operation, and keep chilblain warm and dry locally, otherwise it is easy to recur. The better treatment methods are: (1) Insist on soaking the affected area with 40℃ water temperature. (2) Neomycin Sulfate Cream or Furacillin Cream for external use, with an effective rate of 85-95%. The main measures to prevent the recurrence of chilblain are: (1) keeping the room cold, warm and damp-proof, keeping the indoor temperature above 15℃ and the relative humidity around 50%. (2) Keep shoes and socks, insoles and gloves dry. People with sweaty feet should not wear rubber shoes and use antiperspirant powder. Precautions and prevention of chilblain: To prevent problems before they happen, you should exercise regularly to improve your body's adaptability to cold. And pay attention to the whole body and local warmth, wear gloves as soon as possible, keep your shoes and socks warm and loose, and keep your hands and feet dry. Food should have enough fat, protein and vitamins to ensure that the body has enough calories. Massage the auricles of hands and feet regularly at ordinary times to promote blood circulation of hands and feet. Patients with repeated frostbite every year can use ultraviolet rays to irradiate the frostbitten parts before winter to play a preventive role. After suffering from chilblain, it is advisable to treat it as soon as possible. Chilblain cream and mink oil antifreezing cream have certain curative effect. In addition, the people of China have accumulated rich experience in treating frostbite in their long-term life practice and created many effective prescriptions for treating frostbite. Now the prescription is as follows: (1) Focus persimmon peel with honey or vegetable oil for external application. (2) Solanum melongena root, onion and pepper decoction are used to fumigate and wash the affected area. (3) 50g of cassia twig and 50g of perilla are decocted and soaked in water. (4) Decocting 3-4 slices of fresh orange peel, 300g of ginger and 2000ml of water for 30min, taking out the residue, soaking, and covering the residue. (5) Take 50 grams of oleander leaves, add 500 ml of water, and soak the affected area with decoction. Note that this prescription is prohibited when there is ulcer. (6) Crataegus pinnatifida is pitted and mashed, applied to the affected area, and wrapped with gauze for 3 days, which has a good effect on recurrent chilblain, and should not be used when there is ulcer. (7) Guifu Decoction: 20 grams of cassia twig, 20 grams of safflower, 20 grams of aconite root, 20 grams of Schizonepeta tenuifolia and 20 grams of perilla leaf. Soak the affected area with 3000 ml of decoction and rub the affected area with the residue. (8) 9 grams of kansui and 9 grams of licorice, 2000 ml of water, decocted and smoked the affected area. (9) Burn the old loofah into charcoal, grind it into fine powder, mix it with lard and apply it to the affected area. (10) Red scarf wine: angelica 60g, safflower 30g, pepper 30g, camphor 15g, cinnamon 60g, asarum 15g, dried ginger 30g, 95% alcohol 100ml, soaked for 7 days, and then externally applied to the affected area. (1 1) Erwu fennel wine: Radix Aconiti 30g, Radix Aconiti Kusnezoffii 30g, Fructus Foeniculi 30g, Camphor 30g, Flos Carthami 20g, Ramulus Cinnamomi 15g, soaked in alcohol for one week, and rubbed with medicinal liquor. (12) ziyun ointment: 30g of Arnebia euchroma, 30g of Angelica sinensis, 250g of flaxseed oil 1 ml, and yellow wax. It is made into ointment and applied externally to the ulcer surface caused by chilblain. (13) 25g of camphor, 0/0g of cuttlebone/kloc-0 and 0/50g of vaseline/kloc-0 were mixed into paste and applied externally to the ulcer surface. For stubborn chilblain, you can take Chinese medicine orally. The prescription is: 9 grams of Radix Codonopsis, 0/5 grams of Radix Astragali/Kloc-,6 grams of Radix Aconiti Lateralis Preparata (decocted first), 9 grams of Ramulus Cinnamomi, 9 grams of Radix Angelicae Sinensis, 9 grams of Radix Salviae Miltiorrhizae, 6 grams of dried tangerine peel, 6 grams of dried ginger, 6 grams of roasted licorice, and those with obvious cold; 9 grams of peach kernel and 9 grams of safflower are added to patients with obvious blood stasis syndrome. (14) Daphne genkwa water: licorice 15g, Daphne genkwa15g; Preparation method: water 1000 ml, decocting several times to get juice; Usage: Wash the fester while it is hot, and then change the dressing with coptis gauze; Efficacy: detumescence and pain relief, used for chilblain, and also has a good effect on I ~ II degree frostbite.