Local action cold causes frostbite. There are four degrees of frostbite.
Frostbite I degree characterized the purple colour of the skin and swelling. These frostbite heal completely after 3 to 7 days. Sometimes a few days there is a slight peeling at the site of frostbite and saved increased sensitivity to cold.
If frostbite II degree with bloody blisters-serous content, hyperemia and oedema of the tissue around it. Bubbles appear on the 1st or 2nd day. Healing occurs in 10-20 days without scarring. Can long be preserved hypersensitivity frostbitten areas to cold.
If frostbite III degree observed necrosis of soft tissues. Leather deathly pale or bluish, sometimes blisters with hemorrhagic content. With the development of demarcation inflammation rejected the necrotic tissue and slowly heal with scarring. Healing lasts 1-2 months and more, depending on the depth of necrosis.
If frostbite IV degree developing necrosis of the bones and rejection of dead body parts (the fingers, hands, feet).
In forensic practice are documented cases of frostbite when leaving in a helpless state, as the result of negligence, under the influence of alcohol, a prolonged stay in a cold transport, sports, skiers and mountain climbers. Possible deliberate self-harm by frostbite. Frostbite are mainly found in areas with cold, harsh climate, but can occur in temperate climates with high humidity.