<unk>  is a skin injury that occurs when exposed to extreme low temperatures, causing the freezing of the skin or other tissues, commonly affecting the fingers, toes, nose, ears, cheeks and chin areas. Most often,<unk>  occurs in the hands and feet. The initial symptom is typically numbness. This may be followed by clumsiness with a white or bluish color to the skin. Swelling or blistering may occur following treatment. Complications may include hypothermia or compartment syndrome. People who are exposed to low temperatures for prolonged periods, such as winter sports enthusiasts, military personnel, and homeless individuals, are at greatest risk. Other risk factors include drinking alcohol, smoking, mental health problems, certain medications, and prior injuries due to cold. The underlying mechanism involves injury from ice crystals and blood clots in small blood vessels following thawing. Diagnosis is based on symptoms. Severity may be divided into superficial (1st and 2nd degree) or deep (3rd and 4th degree). A bone scan or MRI may help in determining the extent of injury. Prevention is by wearing proper, fully-covering clothing, maintaining hydration and nutrition, avoiding low temperatures, and minimizing strenuous physical activity while maintaining a sufficient core temperature. Treatment is by gradual rewarming, generally from cold to warm water, and should only be done when consistent temperature can be maintained and refreezing is not a concern. Rapid heating or cooling should be avoided since it could potentially cause heart stress or cause burning. Rubbing or applying force to the affected areas should be avoided as it may cause further damage such as abrasions. The use of ibuprofen and tetanus toxoid is recommended for pain relief or to reduce swelling or inflammation. For severe injuries, iloprost or thrombolytics may be used. Surgery is sometimes necessary. Amputation should be considered a few months after exposure in order to consider whether the extent of injury is permanent damage and thus necessitates drastic treatment. Evidence of<unk>  occurring in people dates back 5,000 years. Evidence was documented in a pre-Columbian mummy discovered in the Andes. The number of cases of<unk>  is unknown. Rates may be as high as 40% a year among those who mountaineer. The most common age group affected is those 30 to 50 years old.<unk>  has also played an important role in a number of military conflicts. The first formal description of the condition was in 1813 by Dominique Jean Larrey, a physician in Napoleon's army, during its invasion of Russia.
Frostbite
Chilblains
Crossbite
Trench foot
Overbite
Snakebite
Abrasion 
Nasal fracture