frostnip

Last reviewed 02/2021

Frostnip

Frostnip is the mildest form of cold injury where there is freezing of the superficial layers of the skin (1).

• may be caused from
• exposure of the skin to very cold temperatures, often with windy conditions
• skin contact with cold surfaces (eg, metal, equipment, liquid)
  
  
• tissues are not permanently damaged
  
  
• may precede frostbite
  
  
• there is intense vasoconstriction of the exposed skin, usually cheeks, ears, or nose.  

The condition is most likely to be experienced by skiers and others who participate in outdoor winter sports, affecting the nose, ears, or tips of digits. Ice crystals are seen as frost on the surface of the skin.

• affected part feels cold and is painful to touch
• a tingling sensation is followed by numbness
• no feeling when the affected part is moved
• skin looks mottled– white and pink (3)

Recovery of the injured part is usually seen with gentle re-warming e.g - by blowing warm air on it (with cupped hands over the nose), placing the area against a warm body part or gaining shelter that protects from the elements. Rubbing of the affected area should be avoided (2).

Rewarm by immersing the affected part into a water bath of 105°-110°F for 25-40 minutes can also be attempted

• temperature should be monitored carefully using a thermometer (higher temperatures may damage tissue)
• maintain the water temperature by adding additional warm water (do not directly add water to the affected area)
• thawing is complete when the part is pliable and colour and sensation has returned and there may be significant pain
• dry heat should not be used to rewarm since it cannot maintain a temperature between 105°-110°F

The warmed tissue becomes hyperemic without blistering, and decreased sensation or tingling may persist for weeks (4). Once rewarmed

• wrap the injured area with a sterile gauze and protect it from movement and further cold since refreezing causes extensive tissue damage and may result in tissue loss
• emolients can be applied 

Note:

• a second episode of frostnip occurring during the same winter and in the same limb as a first episode is regarded as superficial frostbite, rather than recurrent frostnip (5)

Reference:

• (1) Cappaert TA et al. National Athletic Trainers’ Association Position Statement: Environmental Cold Injuries. Journal of Athletic Training. 2008;43(6):640-658
• (2) Nagpal B, Sharma R. Cold Injuries : The Chill Within. Medical Journal, Armed Forces India. 2004;60(2):165-171.  
• (3) Government of UK. Ministry of defence. Joint Service Publication (JSP). Heat illness and cold injury: prevention and management (JSP 539) 2017
• (4) Mohr WJ, Jenabzadeh K, Ahrenholz DH. Cold injury. Hand Clin. 2009;25(4):481-96. 
• (5) Government of UK. Ministry of defence. Synopsis of causation. Cold injury 2008