4-year-old children with a runny nose for more than twenty days may be related to hypertrophic rhinitis, chronic sinusitis and so on. 1. hypertrophic rhinitis: may be acute rhinitis treatment is not timely, nasal septum deviation, malnutrition, etc. caused by chronic inflammation of the nasal mucosa, appear long-term runny nose. 2. Chronic sinusitis: may be acute sinusitis repeated episodes are not completely cured, resulting in mucosal edema and thickening as a characteristic. There will also be a runny nose, nasal congestion, headache and other symptoms. 4-year-old children with a runny nose for more than twenty days, can also be seen in other causes, such as allergic rhinitis, etc., it is recommended to consult a doctor in a timely manner, follow the doctor’s instructions for the relevant examination, with the help of the doctor to clarify the cause, and targeted treatment or treatment.