Trench foot is a condition of the foot where the foot becomes numb, turns either red or blue and starts to have the odor of dying flesh. It is common in those who are in the military. The term “trench foot” got its name from the great number of soldiers who were fighting in trenches in World War I who came down with the condition. Trench feet can lead to swelling, blistering, open sores and if untreated, may result in gangrene. Gangrene is always a serious condition of the foot because it may lead to the amputation of the foot, which causes even more problems. Cause Trench foot is caused by prolonged exposure of feet to the elements, such as coldness (less than 50 degrees Fahrenheit, dampness, water immersion, or other unsanitary conditions along with constricting footwear. Prolonged exposure is defined as less than 12 hours in these conditions, which make it easy for fungi to grow and invade the foot. Trench foot is worsened by sweaty feet. Treatment and Prevention Trench foot should be treated medically to prevent amputation. Prevention involves keeping the feet warm and dry, which may be impossible for soldiers in extreme situations. Changing socks frequently is often the best preventive measure that can be taken.