In cold weather, the number of patients with urticaria in the dermatology department of Tianjin Zhongyan Affiliated Hospital continues to increase. Dermatologists who inquire about medical history have found that many patients do not have a clear cause of ingestion or inhalation. Dermatology chief physician Nie Zhenhua introduced that in cold winter, when the skin encounters cold, clusters of rashes will appear, which is cold urticaria, a common type of urticaria in physical urticaria. Cold stimulation of the whole body or local area leads to increased sensitivity of the nerves, resulting in wind and itching on the skin. Urticaria is a heterogeneous disease characterized by wheals and/or vascular edema. It can be divided into two categories based on the duration of the disease: acute and chronic urticaria. The dividing line between acute and chronic urticaria is usually 6 weeks, and it is often characterized by itchy wheals that appear in batches and vary in size. They disappear within 1-3 hours and generally do not exceed 24 hours, leaving no trace after disappearance. In clinical practice, there is also an induced urticaria, commonly seen as contact urticaria, cold urticaria, high fever urticaria, and solar urticaria, which have special triggers. After removing the triggers, the rash cluster can disappear. Why is it easy to get urticaria in winter? Due to the decrease in winter temperatures and dry air, the reproduction of bacteria and fungi in nature has decreased, but respiratory virus infections have not decreased. Therefore, urticaria induced or exacerbated by viruses still occurs frequently. Secondly, it is currently winter and the temperature is relatively low. There is a large temperature difference between indoors and outdoors. Whenever you suddenly enter a warm indoor environment from a cold outdoor environment or undress and fall asleep, your skin may immediately develop patchy red bumps, accompanied by severe itching symptoms. Scratching can cause them to form patches and ultimately worsen the symptoms of urticaria. Another factor is a certain degree of familial inheritance. In cold urticaria, familial cold urticaria is a chromosomal dominant genetic disease with a family history, which starts from infancy and often lasts for a lifetime. How to distinguish cold urticaria? After contact with cold water or other cold substances, patients with cold urticaria may experience itching, edema, and wind masses in the affected area, which can disappear in about half an hour to an hour. Cold urticaria is more common in exposed areas such as the face and hands. In severe cases, other areas may also be affected. Mucosal areas such as the mouth, tongue, and throat can also experience edema and even abdominal pain when exposed to cold food or drinks. How to avoid cold urticaria? Avoid contact with cold. In winter, attention should be paid to keeping warm and adding clothes in a timely manner. To reduce the entry of cold air and cold air into the body, try to wear scarves, masks, and gloves when going out. Avoid allergenic, spicy, and stimulating foods, as well as cold foods. Eating more fresh vegetables, fruits, and foods rich in vitamin B6, such as grapes, Job's tears, apples, bananas, etc., can effectively control the onset of urticaria. Actively participate in physical exercise, improve the body's ability to adapt to weather changes, especially pay attention to skin cold resistance exercise, and actively prevent cold urticaria. When taking a shower, the water temperature should not be too hot, do not use alkaline soap, and do not use other cleaning agents too frequently to avoid excessive loss of sebum. It is advisable to wear soft and loose cotton fabrics for underwear, and quit smoking and drinking to avoid inducing skin itching. Scratching should be avoided as much as possible to avoid increasing skin lesions and worsening itching. (Reporter Di Hui) (Li Xinshe)