The main causes of children sniffling are environmental stimulation, sinusitis, colds and so on. 1. Environmental stimulation: if the air is too cold or contains a lot of irritating gases, stimulating the nasal mucosa to increase secretion, causing a runny nose, the age of the child does not know how to blow his nose, he will always sniff. 2. Sinusitis: children with sinusitis, the sinuses in the inflammatory medium infiltration, will secrete inflammatory secretions, when these secretions along the nasal outflow, can cause the child old sniffling. 3. Colds: Colds are also known as upper respiratory tract infections, viruses and other pathogenic infections, stimulate the nasal mucosa to secrete nasal mucus, nasal mucus blockage of the nasal cavity leading to breathing problems, the child will always sniffle. Children old sniffling, there may be bad habits and other causes, to go to the regular hospital in time to identify the cause, and under the guidance of a professional doctor to choose the right method for their treatment.