The common causes of frequent runny nose and sneezing are acute rhinitis, allergic rhinitis and vasomotor rhinitis. 1. Acute rhinitis: mostly due to the invasion of upper respiratory tract viruses, causing damage to the mucous membrane of the upper respiratory tract, capillary swelling and congestion. When the nasal cavity is stimulated, the symptoms of frequent runny nose and sneezing will appear. As the disease progresses, systemic symptoms such as loss of appetite and low-grade fever may also occur. 2. Allergic rhinitis: If the patient is exposed to allergens such as pollen, dust, mites, etc., the nasal mucosa will be stimulated and allergic reactions will occur, resulting in frequent runny nose and sneezing, which can be perennial and seasonal. 3. Vasomotor rhinitis: mostly related to autonomic dysfunction, such as inhalation of dry and cold air, irritating gases, or anxiety, tension and other emotional changes, may lead to the onset of this disease. Its main manifestations are frequent sneezing, runny nose, itchy nose and nasal congestion. Symptoms can be recurrent or intermittent. When frequent runny nose and sneezing occur, it is recommended to go to a regular hospital in time for a systematic examination to clarify the cause of the disease.