Frostbite is the change in the skin and subcutaneous tissue due to localized cold injury when exposed to temperatures < 2 degrees C. Some predisposing factors include:

1. wet skin
   
2. extreme wind chill
   
3. constricting garments
   
4. contact with cold metal
   
5. Individuals with altered mental status who are unable to get out of the cold

1. direct cold injury to cells
   
2. ice crystallization of tissues
   
3. poor circulation to the area
   
4. During rewarming, blood vessels leak fluid into the interstitium causing edema. After reperfusion, edema increases and there is cellular swelling as well.

1. Most often affects fingers, toes, noses, and ears.
   
2. Usually graded by degrees similar to burn injuries
   
   1. 1st degree- hyperemia, burning and aching sensation
      
   2. 2nd degree- erythema, blistering, and numbness
      
   3. 3rd degree- may have skin necrosis, deep blisters that may contain blood, initially no sensation but then develop throbbing and shooting pains
      
   4. 4th degree- subcuticular involvement that may include bone in children. Gangrene possible

1. Initial therapy is to rewarm with other body parts or clothing. Avoid rubbing, pressure, and mechanical trauma.
   
2. Thawing and refreezing is associated with more permanent tissue damage and therefore rewarming methods may need to be delayed until definitive measures are available.
   
3. Rewarm with immersion in water between 40-42 degrees centigrade. (104-108F.) Rewarm until the skin is warm, soft, and pliable, usually 30-45 minutes
   
4. Rewarming is often associated with itching and pain, may need analgesics
   
5. Check tetanus immunization status
   
6. Debride blisters and dead tissue, keep area clean
   
7. Elevate to decrease the formation of edema
   
8. Sterile dressings
   
9. Prophylactic antibiotics are controversial.
   
10. If injury is severe, surgical consultation to direct further management.
    
11. Vasodilatation agents may be helpful.

1. Cold sensitivity
   
2. Atrophy of muscle, bone, nerves, and tendons
   
3. Arthritis
   
4. Vasospastic attacks
   
5. Hyperesthesias