Recurrent colds may be caused by factors such as weak personal constitution, poor living environment, bad living habits, and the presence of diseases that affect immunity. 1. Individuals with weak physique: Some people may have weak physique due to premature birth or malnutrition after birth, and the mucous membrane defense function is low, which may lead to recurrent colds. 2. Poor living environment: If you live in an environment with poor sanitation, high population density and lack of ventilation for a long period of time, which leads to a higher content of viruses and other pathogenic microorganisms, the chances of infection may increase, and thus recurrent colds may occur. 3. Bad living habits; such as not paying attention to keep warm, overwork, long-term high mental tension or staying up late for a long time. Existence of diseases that affect immunity: If diabetes has poor blood sugar control for a long time, it may lead to the weakening of its own body’s defense function, which may lead to recurrent colds. Patients with nephrotic syndrome may have a large amount of protein excreted from the urine, which may include immunoglobulin, leading to decreased immunity. In addition to this, the presence of cold symptoms is not necessarily a cold. For example, recurrent runny nose may be caused by rhinitis or sinusitis, and recurrent cough may be cough variant asthma. When a recurring cold occurs, you should seek medical attention in a timely manner, complete the relevant examinations under the guidance of the doctor, clarify the cause of the disease, and actively treat it.