Don’t Lose Your Toes – What You Should Know about Frostbite and Immersion Foot

by Joe Alton, M.D. aka Dr. Bones of

Exposure to cold may lead to injuries such as Frostbite and Immersion (Trench) Foot. The focus of survival medical training should be general, but also take into account the type of environment that you expect to live in if a  disaster occurs.   If you live in Miami, it’s unlikely you’ll be  treating a lot of people with hypothermia.  If you live in Siberia, it’s unlikely you’ll be treating a lot of people with heat stroke. Learn how to treat the likely medical issues for the area and situation that you  expect to find yourself in.

One major environmental risk is the effect of ambient temperature.  Humans tolerate a very narrow range and are susceptible to damage as a  result of being too cold or too hot.  Your body has various methods it  uses to control its internal “core” temperature, either raising it or  lowering it to appropriate levels.  The body “core“ refers to the major internal organ systems that are necessary to maintain life, such  as your brain, heart, liver, and others.  The remainder (your skin,  muscles and extremities) is referred to as the “periphery”.

In general hypothermia, the body’s core temperature drops below 95  degrees F.  There are cold-related injuries that occur in the periphery, however, and you might just encounter them if you’re on a winter hike  or if there is a disaster-related grid shutdown.

Two particularly difficult ones to deal with are Frostbite and Immersion (trench) Foot. Frostbite is the freezing of body tissues, and it usually occurs in the  extremities, especially fingers and toes. Sometimes, the ears, nose, and even the lips may be affected.

These conditions usually occur as a result of inadequately preparing  for a trip in cold weather.  If you expect to be outside for extended  periods of time, dress warmly and consider what you would do for shelter and heat if you found yourself stranded somewhere.   You could easily  get lost during a hike in a snowstorm, have your car stall out, or other mishaps, so don’t feel that it couldn’t happen to you.Although I’ve mentioned this before, It may be useful to remember the simple acronym C.O.L.D. This stands for:  Cover, Overexertion, Layering, and Dry:

  • Cover. Protect your head by wearing a hat. This will prevent  body heat from escaping from your head. Instead of using gloves to cover your hands, use mittens. Mittens are more helpful than gloves because  they keep your fingers in contact with one another.  This conserves  heat.
  • Overexertion. Avoid activities that cause you to sweat a  lot.  Cold weather causes you to lose body heat quickly, and wet, sweaty clothing accelerates the process. Rest when necessary; use rest periods to self-assess for cold-related changes. Pay careful attention to the  status of your elderly or juvenile group members.
  • Layering. Loose-fitting, lightweight clothing in layers  insulate you well. Use clothing made of tightly woven, water-repellent  material for protection against the wind. Wool or silk inner layers hold body heat better than cotton does. Some synthetic materials work well,  also. Especially cover the head, neck, hands and feet.
  • Dry. Keep as dry as you can. Get out of wet clothing as soon  as possible. It’s very easy for snow to get into gloves and boots, so  pay particular attention to your hands and feet.



Frostbite is sometimes listed in stages, from minor “frostnip”  to severe cases causing permanent loss of tissue. Initial symptoms of  frostbite include a “pins and needles” sensation and numbness. Skin  color changes from red to white to blue as the condition worsens.  The  skin will begin to harden and may feel “waxy” to the touch. If cold  exposure continues, the color may change to black, indicating that a  condition known as “gangrene” has set in.  Gangrene is the death  of tissue resulting from loss of circulation.  This usually results in  the loss of the body part affected.  Infection may also set in,  affecting the entire body.  This is called “Sepsis” and is  life-threatening.


Immersion foot causes damage to nerves and small blood vessels due to prolonged immersion in cold water.  This condition was previously  called “Trench Foot”, as it was seen commonly in soldiers who spent long periods of time in the trenches of World War I. When seen in areas  other than the feet, this condition is referred to as “chilblains”.   Immersion foot appears similar to frostbite, but might have a more  swollen or “juicy” appearance.


The earlier that cold-related injuries are recognized and treated,  the more likely the victim will recover without permanent damage.  Frostbite or Immersion Foot is treated with a warm water (no more than  104 degrees F) soak of the affected areas.  This is different from  treatment of general hypothermia, which is best treated with warm DRY  compresses in areas that effectively transport heat to the body core,  such as the armpits, neck, and groin.

Follow these tips when treating frostbite or immersion foot:

  1. Carefully monitor every member of your party for signs of frostbite  in cold weather. If possible, get out of the cold and begin the  rewarming process, even if it is just placing the victim’s hands in  their armpits.
  1. Don’t allow thawed tissue to freeze again. The more often tissue  freezes and thaws, the deeper the damage (think about what happens to a  steak that goes from the freezer to outside and back again). If you  can’t prevent your patient from being exposed to freezing temperatures  again, you should wait before treating, but not more than 24 hours.
  2. Don’t rub or massage frostbitten tissue. Rubbing frostbitten tissue will result in damage to already injured tissues.
  3. Don’t use heat lamps or fires to treat frostbite. Your patient is  numb and cannot feel the frostbitten tissue.  As a result, significant  burns can occur.

Rapid action to rewarm cold-damaged tissues is the key to preventing  long-term damage from exposure. Monitor your team members closely, and  you’ll have the best change to succeed, even if everything else fails.


  1. Pack:

    This stuff is nothing to mess with. If you are thinking of preparing for a “grid-down” situation most of your travel will be on foot. These things will kill you.

    I have a friend who spent a lot of time in the jungles of Vietnam. He STILL has issues with his feet! He’s in his 70’s. That’s a long time to go with foot problems.

    Keep your feet dry and warm. Change your socks regularly. You BOB/GHB needs to have several pair of NON-COTTON socks in zip-lock bags in it. Wash your feet daily! Don’t buy cheap boots/shoes for a SHTF situation (or at anytime in my opinion). Most of my damage to my knees can be attributed to wearing the cheapest shoes for running and exercise I could get – BAD PLAN!

    All of my new purchase socks are Merino wool blend socks. I also can get GI green wool ones at some surplus places. I have drawers full because I have found nothing better.

    I also recommend that you use the buddy system to check each others feet, daily. And another warning – many don’t consider politically correct – blacks are very susceptible to foot issues, especially frostbite. And most of us think we can tough it out. I’ve been there with my soldiers in the winter. They started to take it as a race problem, then realized I was right, the manuals were right, as started putting these checks into practice. As a result my unit had no foot issues during our winter exercises.

    (getting off my soap box now. Thanks)

    • PGCPrepper says:

      “All of my new purchase socks are Merino wool blend socks. I also can get GI green wool ones at some surplus places. I have drawers full because I have found nothing better.

      From one “old soldier” to another; could not agree more. I have tons of Merino wool socks. I was an old skool drill sgt for awhile. “Preached” it, dontcha know?

      • As an ex-hospital corpsman stationed in Okinawa, I can tell you that the skin on your feet is your first line of defense. Your feet sweat, and must be checked after each run/hike. If your feet are in wet conditions too long, you may think you have gotten them dry, but you must check for cracking between toes etc, as infection will set in there. You can see in the old WWII war movies the soldiers washing their socks out and hanging them to dry at the end of the day – rule of thumb, a fresh pair goes on every day.

  2. GoneWithTheWind says:

    The way to avoid frostbite on your feet begins well before the cold weather or a trip in the snow. When I lived in Alaska I had a pair of the Army “bunny boots”. Perfect for zub-zero weather. I found them a little awkard so now I have a good pair of Sorel boots and a good pair of insulated high top hunting boots. Like most things planning ahead pays off so having the right equipment means you don’t have to compromise or make do when bad weather happens. Remember the old Air Force saying; dress for the environment you are flyng over. The same thing should aply for a road trip. Today I will drive from the valley to the top of the mountains and I will be dressed for and have with me the proper clothing for snow and sub-freezing weather.

  3. Nebraska Woman says:

    Do not forget ear lobes! Several teachers had to go out in subzero weather to meet the bus kids. One teacher was wearing gold earrings and no hat/muff/scarf. Her earlobes had severe frostbite and she had to go in for surgery. I wore ear muffs and a muffler and had no problems. Of course, kids got off the bus with no coats, gloves, etc. They must be immune to severe cold.

  4. ChandlerX says:

    Please correct me if I am wrong, but this has worked for myself and my father (who learned it in VietNam), vaseline is a great idea if you are going to be in a wet environment for a long period of time. Wool Merino socks are essential but a good slathering of vaseline will give you feet a little bit more protection from exposure to water.
    Trench foot does not always have to happen in a cold environment.

  5. Tactical G-Ma says:

    I agree with all the above. I don’t use vaseline but shea butter or. any good moisturizer is helpful. Once nipped will forever mean over-sensitivity to cold. I found that layering socks that wick moisture away from the skin is helpful. I am one of those people who sweat heavily thru my head and feet. I always travel with a spare pair of shoes and alternate. Having lived in Alaska and North Dakota has taught me much. But trench foot and jungle rot has been a concern in milder climates. Thanks for the reminder…buy good quality, fitting shoes appropriate for your activity. The money is well spent.

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