Prevention and Treatment of Frostbite in the Backcountry

Richard Yocum, MD, San Diego Mountain Rescue Team and Riverside Mountain Rescue Unit

Frostbite is a painful condition often resulting in loss of tissue that is usually preventable. The Wilderness Medical Society (WMS) published a 2019 update to their clinical practice guidelines for the prevention and treatment of frostbite1 , which serves as the primary basis for this discussion along with research by Cauchy et al. in Chamonix, France.2,3 Frostnip and frostbite occur when heat loss exceeds the ability of blood flow to deliver heat to tissues and prevent freezing.

Preventive Measures

• Avoid/minimize duration of exposure to extreme cold conditions, especially wet and high wind-chill

• Maintain adequate hydration and caloric intake

• Maintain adequate core temperature

• Cover all skin/scalp to protect from cold, wind, and moisture

• Use multiple clothing layers including wind protection

• Change from gloves to mittens

• Minimize blood flow restriction from constrictive clothing/footwear and inactivity

• Avoid perspiration and wet extremities

• Consider exercise to increase blood flow to the periphery (unless there is risk of exhaustion)

• Consider warmth from adjacent body heat, such as patient’s own armpit or abdomen

• Consider chemical or electrical warmers for hands/feet

• Minimize effects of known diseases, medications, and substances (alcohol, drugs, tobacco)

• Regularly check all members in group for early signs of frostnip/frostbite

• Recognize early and treat immediately cold-induced numbness/frostnip

Frostnip is a superficial cold injury distinct from frostbite but may precede frostbite. Although frostnip resolves with rewarming without permanent tissue damage, frostnip signals that appropriate action is immediately needed to prevent frostbite. Frostbite is traditionally categorized into 4 grades of severity of tissue damage based on clinical findings immediately after rewarming. Because these distinctions are difficult to assess before rewarming, a 2-tiered classification of superficial vs. deep is more appropriate for the field. A given patient may present with frostbite in more than one location with varying grades of severity.

Some treatment recommendations may be generalized to most cases of frostbite. 

Treatment General to All Frostbite

• Remove jewelry/other constrictive material from affected body part

• Assure adequate hydration and caloric intake

• Treat any underlying hypothermia (if mild, treat concurrently with frostbite; if moderate-

severe, treat before treating frostbite)

• Start ibuprofen at a dose of 12 mg/kg divided twice daily to maximum 2400 mg/day in 4

divided doses (e.g., for 70 kg patient, 400 mg twice daily to 600 mg 4 times daily)

(Nonsteroidal drugs such as ibuprofen can reduce vasoconstriction and tissue damage)

• If available, supplemental oxygen if hypoxic (O2 sat < 88% or elevation > 4000 m/13,000’)

• Do not debride/open blisters in the field

• Do not rub/apply ice or snow

Criteria for Field Rewarming

• No chance of refreezing

• Definitive care > 2 hours distant

• Ability/equipment available to thaw

The most important decision is whether to thaw frozen tissue in the field. Refreezing is devastating. If there is a risk of thawed tissue refreezing, do not thaw; keep the affected tissue frozen until a thawed state can be maintained, such when out of the field. However, tissue should not be intentionally kept frozen if environmental conditions allow for spontaneous thawing; frozen tissue should be allowed to thaw. Active rapid warming is preferred over slow passive warming. Rewarming in the field should adhere to clinical practice guidelines and anticipate the need to manage significant pain.