Cold Environment-Associated Extremity Lesions or Severe Hypothermia Help Differentiate Between Frostbitten and Trench Foot (Immersion Foot).

Cold associated foot injuries, such as frostbite and trench foot (immersion foot) are relatively common in cold environments. The former is classified as a freezing cold injury, and the latter as a nonfreezing cold injury. Trench foot is sometimes misdiagnosed as frostbite, and rapid rewarming exacerbates the condition. This paper aims to help differentiate between frostbitten foot and trench foot. This study included patients with frostbitten foot or trench foot treated at our hospital between December 2005 and May 2023. The differences in sex, age, month of injury, conditions at the time of injury, injury distribution, foot lesion laterality, other complications upon arrival (finger frostbite, immersion hand, or hypothermia), and presence and distribution of sensory disturbance at discharge were noted among the groups. A total of 16 patients (14 men) with frostbitten foot and 3 patients (3 men) with trench foot were identified. Finger frostbite observed in nine and zero patients with frostbitten foot and trench foot, respectively; and severe hypothermia on arrival observed in five and zero patients with frostbitten foot and trench foot, respectively. Physical findings at the initial examination showed that the frostbitten feet were dry, and the lesions were distal and clearly demarcated, whereas feet with trench foot were wet, and the lesions covered the entire sole and were not clearly demarcated. Accurate differentiation between frostbitten foot and trench foot and appropriate initial treatment are important. The presence of finger frostbite, immersion hand or severe hypothermia may help to differentiate between frostbitten foot and trench foot.