Medical · Emergency · Intermediate
Frostbite and Trench Foot: Prevent It, Treat It
Two cold injuries that come from different problems — freezing and wet — with different first aid.
This is for educational purposes only. Not professional medical, electrical, or safety advice.
Warning
Never rewarm frostbitten tissue with dry heat, a fire, or by rubbing with snow. Blisters are a sign of real tissue damage and need medical care.
- 01
Spot frostbite early
Skin goes numb, waxy, white or grayish-yellow and feels firm. Deep frostbite feels hard and the joint won't bend. Numbness means stop now — you've lost the warning system.
- 02
Do not rewarm if it can refreeze
Refreezing thawed tissue causes far worse damage than leaving it frozen. If you must walk out, keep it frozen and protect it.
- 03
Rewarm correctly
Immerse in 100–105°F water (test with your elbow — it should feel comfortably warm, not hot) for 15–30 minutes. Never dry heat, never a fire, never rubbing. Expect painful return of feeling; that's the blood coming back.
- 04
Protect it after
Don't pop blisters, don't drain them. Dry gently, wrap loosely, put gauze between fingers and toes, keep the part warm and off the ground. Evacuate — frostbite needs a clinic.
- 05
Prevent trench foot
It comes from wet and cool (40–60°F) for hours, not from freezing. Two sock sets rotated and dried daily, foot powder, feet aired at every break, change socks before bed, keep feet out of standing water.
- 06
Treat trench foot
Dry it slowly, warm not hot, elevate, no walking if numb or blistered. It takes weeks to heal and repeated damage is permanent — the fix is prevention, every single day.