There are very many reasons for having a runny nose every day, and the specific reasons are as follows:1. Rhinitis: If it is clear nasal discharge, the more common causes are chronic rhinitis, hypertrophic rhinitis, allergic rhinitis.2. Sinusitis: If it is pus or yellow nasal discharge, it may be due to chronic sinusitis, fungal sinusitis.3. Other: There are also some patients who suffer from nasal polyps, deviated septum, and tumors of the nasal cavity and sinuses. Other. Specific causes of individual differences, after the onset of the recommended to the ear, nose and throat department, you can do routine blood tests, nasal endoscopy, which helps to determine the initial condition. Some patients have more complicated conditions, need to do sinus CT examination, after clarifying the condition can be targeted treatment, the need for regular follow-up, observation of the effect.