WWII poster: "This is trench foot"

World War II poster from the U.S. National Archives warning about trench foot.

by James Hubbard, M.D., M.P.H.

Trench foot, also called immersion foot, was common in soldiers who had to spend hours upon hours standing in trenches with cold water up to their ankles or knees. But it can occur in anyone who stands in cold water (33 to 59 F) or wears wet socks or shoes for long periods in the cold. It usually takes ten hours or longer of these constant conditions—the cooler the quicker. Think campers or water-related disasters.

The constant cold wetness injures the tiny blood vessels that bring nutrition to your feet, leading to foot-tissue damage. Problems range from burning and aching to muscle, nerve, and skin destruction. Trench foot can trigger years of painful, swollen feet, or even partial loss of a foot or feet. There’s no real cure for trench foot, so prevention is essential.

If you have no choice but to go long periods with wet feet, the following helps prevent trench foot:

  • Clean, then air dry your feet for eight out of twenty-four hours (preferably eight hours straight). This means no socks. Lying down helps with circulation.
  • Wipe your shoes or boots out, and allow them to dry.
  • Change into dry socks a minimum of three times a day.
  • Keep the rest of your body warm.
  • Move your legs around, walk, work your toes, raise up and down on your toes—anything to get the blood flowing.

Early Symptoms of Trench Foot

  • Blanching or mottled skin
  • Swelling
  • Cramping
  • Numbness

Treatment of Trench Foot

Gently warm the feet. Five minutes of soaking in warm, not hot, water may help. Or just air warm.

A few hours after warming, the feet may become:

  • Red
  • Painful—even throbbing and severe.
  • Swollen more
  • Sensitive to light touch

Later you can develop:

  • Skin or muscle damage
  • Rashes
  • Numbness
  • Aching
  • Episodes of extreme foot sweating
  • Episodes of blistering

If areas of the skin turn black, that means tissue is dying. You need to get medical help if at all possible. If you can’t, start antibiotics if you have them. You will need to start treating it as a wound prone to infection and more damage.