What causes postnasal drip?

The nose normally makes mucus that drains unnoticed. A cold, [Allergic Rhinitis](/conditions/allergic-rhinitis/), smoke, dust, dry air, or other irritation can increase production or make mucus thicker. [Sinusitis](/conditions/sinusitis/) and [Chronic Sinusitis](/conditions/chronic-sinusitis/) may cause ongoing congestion, facial pressure, and drainage. Some people feel throat mucus because [Acid Reflux](/conditions/acid-reflux/) irritates the throat and triggers clearing, even when nasal mucus is not the main problem. The sensation can cause throat clearing, hoarseness, a tickly cough, bad breath, or a feeling of something stuck.

Notice whether symptoms follow dust, pets, seasonal changes, meals, lying down, or a recent cold. Drink fluids, avoid smoke, and consider a saline nasal rinse made with sterile or previously boiled and cooled water. A pharmacist or clinician can advise whether an antihistamine, nasal spray, or reflux treatment is suitable; treatment depends on the cause. Persistent cough should be assessed rather than assumed to be drainage. Read about [Postnasal Drip](/symptoms/postnasal-drip/) and [Chronic Cough](/conditions/chronic-cough/) for related symptoms.

Arrange a review if drainage lasts, keeps returning, disrupts sleep, or comes with facial pain, reduced smell, wheezing, fever, or a cough that is not settling. Seek urgent help for severe breathing difficulty, swelling around an eye, sudden severe headache, confusion, or inability to swallow fluids. A clinician can examine the nose and throat and distinguish allergy, sinus disease, reflux, infection, or another cause.

Ask whether your pattern fits allergy, sinus inflammation, reflux, or another cause; whether a nasal examination is needed; and which treatment is safe with your current medicines. Mention one-sided blockage, blood-stained mucus, voice change, or symptoms that began after a new medicine.