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Chapter 12
FROSTBITE/IMMERSION FOOT
Recommendations are considered Category 1B by the WMS Panel of Expert Reviewers
I. GENERAL INFORMATION
Frostbite is localized injury or death of tissue from exposure to subfreezing cold. The
chance of damage is increased by: 1) temperatures 24ºF (-4.5ºC) or below, 2) high winds,
3) high altitude, 4) use of tobacco, alcohol, or other drugs, 5) contact with heat-
conductive materials, such as metal, water, or gasoline, 6) overexertion, which produces
fatigue and sweat, and 7) previous frostbite injury.
Measures to help prevent frostbite include: 1) avoiding tight boots or too many
pairs of socks in larger boots, 2) preserving heat by keeping head, neck, and face covered,
3) wearing mittens instead of gloves, 4) staying well-hydrated, 5) maintaining metabolic
heat production with adequate caloric intake, 6) keeping dry, and 7) avoiding direct skin-
metal or skin-fluid contact.
Immersion foot (trenchfoot) is a cold weather, non-freezing injury resulting from
vasoconstriction of the arterioles with subsequent loss of heat and oxygen supply to
surface tissues.
Prevention includes 1) avoidance of tight-fitting footwear, 2) changing into dry
socks regularly (at least once a day), and 3) periodic (every 4 hours in extreme wet and
cold conditions) air-drying, elevation, and massaging of feet to promote circulation.
II. GUIDELINES FOR ASSESSMENT AND TREATMENT
Superficial frostbite (frostnip): A small patch of skin is white, but rapidly returns to
normal with warm breath or skin-to-skin rewarming. No special treatment required.
Partial Thickness frostbite: The skin is pale, cold, and numb, but underlying tissues
remain soft and pliable. Treat superficial frostbite with passive skin-to-skin contact or
rapid rewarming, but avoid heat exposure greater than 108°F (42°C). After thawing, a
few clear fluid-filled blisters develop in superficial frostbite. If damage is extensive,
blisters may fill with bloody fluid, and treatment should be administered as in deep
frostbite (see below). Extreme care must be taken with frostbitten tissue to prevent
refreezing. Evacuate as soon as possible if blisters have formed. This can be a self-
evacuation if the hands are involved, but might require a litter evacuation if the feet are
affected. Give ibuprofen every 6 hours to inhibit thromboxane production. Maintain
adequate hydration. Protect blisters with clean gauze or cloth bandage.
Full Thickness (Deep) frostbite: Skin and deep structures, including muscle, tendons, and
possibly even bone are involved. The affected part is hard and not pliable. On diagnosis
of deep frostbite, evacuate patient immediately. Patients with frostbitten, unthawed feet
may walk to self evacuate. During evacuation, if possible, protect the affected part with
dry insulation, such as clean dry socks or dry mittens. Remove jewelry and all
constrictive clothing. After evacuation, or if transportation is certain, rapidly rewarm the
frostbitten area in water pre-heated to 100.4 to 104° F (38 to 40° C). After thawing,
