The common causes of constant sneezing and nasal congestion include allergic rhinitis, vasomotor rhinitis, non-allergic rhinitis with eosinophilia syndrome and so on. 1. Allergic rhinitis: If patients inhale allergens such as dust, mites, oil smoke, etc., it will cause irritation to the nasal mucosa, making the nasal cavity appear hypersensitive, leading to the onset of the disease, and then the manifestation of constant sneezing, nasal congestion, and watery nasal discharge. 2. Vasomotor rhinitis: patients can be induced by mental stress, endocrine disorders or changes in environmental temperature, which can trigger the onset of this disease, resulting in nasal hypersecretion, which leads to the phenomenon of clear nasal discharge and nasal congestion, and is usually accompanied by sneezing and itchy nasal passages. 3. Non-allergic rhinitis with eosinophilia syndrome: it is a kind of high reactive rhinopathy with unknown cause, and a large number of eosinophils can be found in nasal secretion smear, which can be manifested as sneezing and nasal congestion all the time, and also have the symptom of running clear nose. If sneezing, nasal congestion and other uncomfortable symptoms always occur, it is recommended to consult a doctor in time to clarify the diagnosis and targeted treatment.