“Prolonged sniffling is generally caused by inflammation of the mucus membranes inside the nose. If not an allergic reaction, it could be caused by hormone shifts, like from hypothyroidism or pregnancy. Also, some drugs, such as certain blood pressure medications, cocaine, and even nasal decongestant sprays, can cause what’s called rebound congestion if you use them for more than a few days. Another possibility: chronic rhinosinusitis, an inflammation inside the sinuses and nasal passages. We can’t always pinpoint a reason for nonallergic rhinitis, but whatever the cause, it usually responds well to nasal steroids or antihistamines.” — Leslie C. Grammer, allergist and immunologist at the Northwestern Medicine Sinus and Allergy Center