Trench foot (also called immersion foot) is a condition that happens when your feet spend a long time in a cold, wet environment. Your feet might become numb, discolored, and swollen. Trench foot can be painful, but it’s easy to prevent and treat.
The History of Trench Foot
The first person to describe trench foot was a surgeon in Napoleon’s army. It became common in World War I, when soldiers would stand for hours in muddy trenches. Later, during World War II, shipwrecked sailors would get it after spending time in lifeboats that were full of water. Trench foot made a comeback among troops during the Falkland Islands conflict of 1982.
Eventually, people realized that damp, cold conditions were at fault. “The military basically wiped it out in the World Wars, especially World War I, by just bringing people fresh, dry socks,” says Ken Zafren, MD, a clinical professor of emergency medicine at Stanford University.
This simple strategy has gone a long way. People still get trench foot today, but it’s much less common than it used to be.
“The good news is that most people are not going to get trench foot because most people are not exposed [to these conditions],” says David Armstrong, PhD, the director of the University of Southern California Limb Preservation Program.
What Causes Trench Foot?
You can get trench foot when your feet are cold and wet for a long time. When you’re cold and wet, the small blood vessels in your feet narrow. This can cut off blood flow and cause nerve problems. Over time, the blood vessels weaken and break down, leading to more damage.
Trench foot is a nonfreezing cold injury, which means the temperature is low, but not freezing. It can happen in temperatures as high as 59 F. Once the temperature dips below 32 F, you’re more likely to get freezing injuries like frostbite.
Who’s most likely to have trench foot?
Today, trench foot usually affects soldiers in training and combat. But other people can get it, too.
Besides soldiers, the people who are most likely to have trench foot include those who:
- Spend a lot of time outdoors (like hikers or campers) and don’t change out of wet shoes and socks
- Go to music festivals and stand in the mud and cold for long periods of time
- Work in or near water, like in harbors or other marine environments
- Don’t have a safe, dry place to live
Poor nutrition and fatigue may also play a role.
How long does it take to develop trench foot?
It usually takes one to three days to get trench foot. But sometimes, it can happen in 10 to 22 hours.
What Does Trench Foot Look Like?
There are a few phases of trench foot.
Phase 1. At first, your feet may be tingly, prickly, or itchy. Then, they may go numb. Your feet may even feel heavy, which can make it hard to walk. At this point, your feet will probably be discolored. Over time, your feet will become pale and clammy. This is because blood flow gets cut off.
Phase 2. When you get out of the cold, wet environment, your feet may be blotchy as blood flow begins to return. If you’re light-skinned, your feet might turn blue or purple. This color change can be harder to see on dark skin. Your feet may swell, too.
Phase 3. As they get warmer, your feet may turn bright red, depending on your skin tone. They may also feel very sensitive, painful, or strange. Some people might get blisters or sores, which can become infected. In the most serious cases, this stage can last up to six to 10 weeks.
You may feel the effects of trench foot for weeks or years. In some cases, it’s permanent. Your feet will probably look normal but may be extremely sensitive to cold or pain.
Other Trench Foot Symptoms
Depending on the phase, trench foot can cause different symptoms. These include:
- A tingly, prickly, or itchy feeling
- Numbness
- Bright red, dark blue, purple, or very pale skin
- Clamminess
- Pain
- Swelling
- Leg cramps
- Blistering or sores
- Bleeding under the skin
Trench foot usually affects feet, but in rare cases, it can affect your hands, too.
How Trench Foot Is Diagnosed
To diagnose trench foot, your doctor will take a look at your feet. They’ll ask about your symptoms and whether you’ve been in any cold, wet environments recently.
They may want to perform some tests to rule out other conditions, like an infection or frostbite. These tests could include a blood test, X-ray, or bone scan.
How Do You Treat Trench Foot?
If caught early, trench foot is easy to treat. Your foot needs to be slowly, gently rewarmed, ideally in a room-temperature environment. If possible, turn on a fan to avoid rewarming too quickly, which can lead to pain and swelling. You also can try soaking your feet in warm (not hot) water for five minutes.
The most important thing is to keep your feet clean, dry, and warm. You’ll also want to get plenty of rest and raise your feet above your heart while sleeping.
Some medicines can help treat the pain and prevent complications. If your feet hurt, you can take acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs). Your doctor may also prescribe a drug called amitriptyline. A tetanus booster and antibiotics can help prevent infections.
Take care of your feet as they heal. This includes:
- Wearing clean, dry socks during the day
- Avoiding socks while sleeping to prevent your feet from getting sweaty
- Avoiding cigarettes and other nicotine products (Nicotine can make it harder for blood to flow to your feet.)
- Eating a high-protein diet
- Avoiding walking, as it may cause more damage
Check your feet regularly for signs of infection.
Trench Foot Complications
If you have blisters, they can sometimes become infected. This can lead to a deep skin infection called cellulitis and a serious immune system reaction called sepsis.
If blood flow stops completely, you can get a condition called gangrene, in which the tissue begins to die. If you get a serious case of gangrene, your feet may need to be amputated. If left untreated, the complications of trench foot can be deadly. But early treatment can prevent these complications.
“Trench foot is a stark reminder that even in our modern world, basic environmental exposures can still pose serious threats to limb health,” Armstrong says.
How to Prevent Trench Foot
You can easily prevent trench foot by following best practices, such as:
- If your shoes or socks get wet, change out of them as soon as you can. Let your feet air-dry.
- Change your socks every day.
- Wear well-fitting shoes.
The most important thing? “Keep the feet dry,” says Zafren. “Though it might be easier said than done.”
Takeaways
Trench foot is a condition that happens when your feet are cold and wet for a long time. It causes tingling, numbness, and pain. Even though untreated trench foot can lead to dangerous complications, it’s easy to prevent and treat. To avoid it, keep your feet warm and dry.
FAQs About Trench Foot
Here are some frequently asked questions about trench foot.
How common is trench foot today?
Although it was common on World War I battlefields, trench foot is less common today. Most cases are caught and treated early.
Can trench foot be deadly?
If you don’t treat it quickly, trench foot can lead to deadly complications like sepsis, an immune system reaction. But you can avoid these complications completely with early treatment.
Is trench foot an infection?
Trench foot itself isn’t an infection, but in rare cases, it can lead to a deep skin infection called cellulitis and a serious condition called sepsis.
Is trench foot a chronic condition?
Trench foot goes away with treatment. But in some cases, it can have long-term consequences, such as foot pain and sensitivity to cold.