Trench foot, also known as immersion foot syndrome, is a type of non-freezing cold injury. It is a condition that develops when feet are cold and wet for a long time and affects the skin.
Trench foot got its name during the First World War (1914-1918) when around 75,000 British and 2,000 American soldiers developed the condition after spending long periods of time in the cold, wet trenches on the front line.
Later, sailors serving during World War II (1939-1945) also developed the condition, and there are reports of it being experienced by homeless people today.
Fast facts on trench foot:
- Preparing properly for cold, outdoor activities can prevent trench foot.
- In severe cases, the condition can affect the toes, heel, or whole foot.
- Typically, trench foot develops after being exposed to conditions for 1 to 2 days.
Trench foot or immersion foot is a type of tissue damage caused by prolonged exposure to cold and wet conditions. It leads to swelling, pain, and sensory disturbances in the feet. It can lead to damage to the blood vessels, nerves, skin, and muscle.
Trench foot is distinct from frostbite, another form of tissue damage to the feet, in that the skin does not freeze. It is known as a non-freezing cold injury (NFCI).
People who have the condition today do not experience the same level of tissue loss as the soldiers that developed it during the wars.
It is a preventable condition that causes long-term damage and it is not contagious.
Symptoms of trench foot can include:
- tingling or itching
- cold and blotchy skin
- a prickly or heavy feeling
Once the foot warms up, people may notice their foot changes from white to red, eventually becoming dry and painful. Blisters can form, leading to skin and tissue falling off the injured foot.
If trench foot is left untreated, it can lead to gangrene and even the need for amputation.
Cases of trench foot are categorized into one of the four following stages:
- Stage 1 – injury stage: The blood flow is restricted, and the tissue is cold and numb. The limb may be red or white, and there is no pain.
- Stage 2 – immediate post-injury: Once the limb has warmed, it can turn from white to blue and stay cold and numb. There may be mild swelling.
- Stage 3 – hyperaemic phase: This can last from 2 weeks to 3 months. During this time, the limb becomes hot and red, and the skin becomes dry. There is often pain and pins and needles. In severe cases, blisters may develop.
- Stage 4 – post-hyperaemic stage: This may last for the rest of the person's life. They may experience increased sensitivity to the cold, pins and needles, and some pain. There may also be some ongoing ulceration.
Trench foot results from exposure to temperatures of between 0°C to 15°C and the risk increases if the feet are also wet. It occurs when low temperatures restrict blood flow to the affected area.
Some people can develop symptoms after just an hour of exposure; in others, symptoms may not appear for up to a week.
The severity of the injury will depend on the degree of cold, the wetness of the tissue, and how long a person was exposed to the conditions.
Trench foot has also been known to occur among people that fish for a living and homeless people. Studies have also shown that people of African ethnicity are more likely to develop the condition than Caucasians.
Anyone who suspects they have trench foot should seek medical attention. A healthcare professional will examine the foot to decide what stage the trench foot has reached.
While the immediate effects of trench foot can be alleviated, the condition can lead to long-term tissue damage and chronic pain. A person with trench foot may require long-term follow-up care.
The first thing to do is to remove the person from the cold, wet environment and warm the affected limb up slowly. Quickly warming the foot can make the damage worse.
People can take painkillers to ease the pain and should protect any pressure sores.
Other steps include:
- cleaning and drying the feet thoroughly
- wearing clean, dry socks every day
- not wearing socks when sleeping or resting
In serious cases, people will find it difficult to walk because of the swelling, pain, and blisters. They should avoid walking and elevate their feet as this will help to reduce the swelling. Ibuprofen will also help to reduce inflammation.
Hydration, nutrition, shelter, and suitable protective clothing are necessary to prevent trench foot.
When getting ready for outdoor activities, tips include:
- wearing boots that fit well
- wearing thick, wool socks
- keeping the body warm
- removing shoes and socks twice a day to dry and massage the feet
- never sleeping in wet shoes or socks
- drying wet socks against the skin before putting them on if there is no other option
- keeping feet out of water or mud wherever possible
- responding to any tingling quickly
- wearing loose footwear to allow for circulation
To help prevent trench foot, people should take off their wet shoes and socks, and air-dry their feet.