Chilblains usually occur in winter and early spring in my country, and are more common in the Yangtze River Basin than in the north. Although the climate in the Yangtze River Basin is higher than in the north in winter, it is relatively humid, and the cold prevention measures are not as good as those in the northern regions. Children often ignore cold prevention, so chilblains are common. Trench foot and immersion foot used to occur more often during wartime. The former is caused by standing in a trench at 1 to 10 degrees Celsius for a long time, and the latter is caused by standing in cold water. In peacetime, these two types of cold injuries can also occur in certain construction, paddy field labor, or military duty.