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Immersion foot (or hand) is caused by prolonged immersion in cold water or mud, usually below 10°C. Prehyperemic stage is marked by early symptoms of cold and anesthesia of the affected area. Hyperemic stage follows with a hot sensation, intense burning, and shooting pains. Posthyperemic stage occurs with ongoing cold exposure; the affected part becomes pale or cyanotic with diminished pulsations due to vasospasm. This may result in blistering, swelling, redness, ecchymoses, hemorrhage, necrosis, peripheral nerve injury, or gangrene. Secondary complications can include lymphangitis, cellulitis, and thrombophlebitis. The condition was first described during trench warfare in World War I. It is most commonly seen in homeless patients.
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Treatment is best instituted before or during the hyperemic stage. Treatment consists of air drying and gradual rewarming by exposure to air at room temperature (not to ice or heat). Affected parts are elevated to aid in removal of edema fluid. Pressure sites are protected with cushions. Bed rest is required until all ulcers have healed. Later treatment is the same as for Buerger disease (see Chapter 12). Prevention involves properly fitting footwear, improved foot hygiene, and sock changes to keep feet clean and dry.