Hello: The distribution of cold cases is sporadic, does not cause epidemics, often easy to combine with bacterial infections. The common cold has a more rapid onset, early symptoms of dry itchy throat or burning sensation, sneezing, nasal congestion, runny nose, the beginning of the watery nasal discharge, 2 to 3 days after the thick; may be accompanied by a sore throat; generally no fever and systemic symptoms, or only a low fever, headache. It is usually cured in 5 to 7 days. Cold is also a kind of acute infectious rhinitis, commonly known as "cold". It is caused by respiratory viruses, of which coronavirus and rhinovirus are the main causative viruses. Viruses are discharged from respiratory secretions and spread, and infection is easily induced when the body's resistance is lowered, such as by cold, malnutrition, excessive fatigue, excessive alcohol and tobacco use, systemic illnesses, and chronic diseases of the nose itself that affect the smooth flow of the respiratory tract. Secondary bacterial infection after the onset of cold. At the onset of cold, there is dryness and itchiness in the nose, sneezing, general discomfort or low-grade fever, and later on, there is nasal congestion, loss of sense of smell, a large amount of watery nasal discharge, nasal mucosa congestion, edema, and a large amount of watery or purulent secretion, etc. If there is no complication, the duration of the disease is very short. If there are no complications, the course of the disease is about 7-10 days.