White foamy sputum in the nasal cavity, which is the sputum aspirated back through the nasal cavity, is seen in allergic rhinitis, chronic rhinitis, chronic sinusitis and other diseases that cause increased nasal secretions. 1. Allergic rhinitis: Nasal contact with allergens such as airborne dust, animal dander, dust mites, etc., can cause stimulation of the nasal mucosa, resulting in increased nasal secretions. Long-term nasal mucous membrane irritation can lead to chronic inflammation, making the secretion sticky. 2. Chronic rhinitis: chronic rhinitis can lead to nasal mucosa congestion, swelling and thickening, causing submucosal glandular tissue hyperplasia, resulting in surface cilia dysfunction, nasal congestion, nasal discharge and other symptoms, can also be accompanied by white mucus backflow. 3. Sinusitis: chronic sinusitis nasal secretions from the sinuses, is due to inflammation of the sinus mucosa, resulting in secretions from the sinus mouth to the nasal cavity, the inflammation of the infection is mild, manifested as white secretions, secretion reflux will produce white foam sputum. It is recommended to consult a doctor in time to determine the cause of the disease, and actively cooperate with the physician to treat the disease, to avoid aggravation of the condition.