The common causes of old runny nose are acute rhinitis, sinusitis, allergic rhinitis and so on. 1. Acute rhinitis: common symptoms are frequent runny nose, sneezing, nasal congestion and itchy nose after cold. 2. Sinusitis: there may be headache, fever, yellow nasal discharge, nasal congestion, and facial swelling and pain, and repeated episodes of sinusitis will lead to the development of chronic sinusitis, which will lead to the emergence of yellow nasal discharge with nasal congestion, dizziness, memory loss and other symptoms. 3. Allergic rhinitis: allergic rhinitis refers to the allergy of the nasal mucosa to allergens resulting in allergic reaction diseases, the main symptoms include a lot of watery nasal discharge, sneezing, nasal itching, nasal congestion and other symptoms. Frequent runny nose may also be caused by vasomotor rhinitis, etc., and need to go to the hospital. It is recommended that the patient should consult a doctor to clarify the cause of the disease and treat different diseases.