What is post-nasal drip?
The nose and sinuses constantly produce mucus, which normally you swallow without noticing — it helps keep the nose and throat moist and traps dust and germs. Post-nasal drip is what happens when you become aware of this mucus running down the back of the throat, either because more of it is being made than usual, or because it has become thicker and more noticeable. It is an extremely common and usually harmless experience.
The sensation of post-nasal drip can be surprisingly bothersome even though it is rarely serious. People describe a need to clear the throat frequently, a feeling of mucus sitting at the back of the throat, a tickly cough (especially at night or when lying down), or a sensation of a lump in the throat. Understanding what is driving it — most often allergies, an infection or an irritant — is the key to easing it.
Symptoms and how it feels
Post-nasal drip itself is a sensation rather than a disease, and it tends to produce a recognisable cluster of experiences. Common symptoms include:
- •A feeling of mucus dripping or trickling down the back of the throat
- •A frequent need to clear the throat
- •A persistent cough, often worse at night or when lying down
- •A sensation of a lump in the throat
- •A sore or irritated throat from repeated clearing
- •Sometimes hoarseness, or bad breath
What causes post-nasal drip?
Post-nasal drip has several common causes, and identifying the likely one guides treatment. Allergies, such as hay fever, are among the most frequent causes, producing thin, clear mucus alongside sneezing and an itchy or runny nose. Infections like the common cold, flu or sinusitis increase mucus production and often make it thicker and coloured. Sinusitis in particular is a common cause of persistent post-nasal drip with facial pressure.
Other causes include irritants such as smoke, fumes, dry air or strong smells, which stimulate mucus production, and, importantly, acid reflux — where stomach acid rises and irritates the throat, producing a similar sensation of mucus and throat clearing even without much actual drip. Because reflux can masquerade as post-nasal drip, it is one cause worth considering when the usual nasal treatments do not help. Certain medications and hormonal changes can also play a role.
How to relieve post-nasal drip
Relieving post-nasal drip is often a matter of thinning the mucus, clearing the nasal passages, and addressing the underlying cause. Staying well hydrated by drinking plenty of fluids helps thin mucus so it is less noticeable and easier to clear. Saline nasal rinses or sprays are particularly effective, gently washing out excess mucus and irritants from the nose and sinuses, and are safe to use regularly. Steam inhalation and humidifying dry indoor air can also help.
If allergies are the cause, antihistamines and steroid nasal sprays can reduce the mucus at its source, and avoiding known allergens helps. If a sinus infection is responsible, treating the sinusitis addresses the drip. Where acid reflux is the culprit, measures to reduce reflux — such as not eating late, raising the head of the bed, and avoiding trigger foods — can relieve the throat symptoms. A pharmacist can advise on suitable remedies for your likely cause.
Persistent post-nasal drip
Most post-nasal drip is temporary, linked to a cold or a bout of allergies, and settles as the cause resolves. When it becomes persistent or chronic, however, it is worth identifying and treating the underlying cause rather than just living with it, as ongoing throat clearing and coughing can be tiring and irritating. Chronic post-nasal drip is a common cause of a lingering cough, and treating the drip often resolves the cough.
Persistent post-nasal drip is frequently due to ongoing allergies, chronic sinus problems, or acid reflux, each of which has specific treatments. A doctor can help work out which is responsible, sometimes by trying treatments for the most likely cause and seeing what helps. Because the causes overlap and can coexist, this may take a little trial and error, but persistent throat mucus can usually be improved considerably once the driver is identified and treated.
When to see a doctor
Post-nasal drip is usually harmless, so it does not normally need medical attention and can be managed with simple measures. However, you should see a doctor if it is persistent and not improving with self-care, as identifying the underlying cause — allergy, sinusitis or reflux — allows more effective treatment. It is also worth seeking advice if post-nasal drip is causing a troublesome ongoing cough or significantly affecting your sleep or daily life.
Certain features warrant more prompt assessment: mucus that is persistently one-sided, blood-stained mucus or phlegm, foul-smelling discharge, or post-nasal drip accompanied by significant facial pain, fever, or difficulty swallowing. These are uncommon but can point to a sinus infection needing treatment or, rarely, something that needs closer evaluation. For the everyday, common experience of post-nasal drip, though, simple self-care is usually all that is needed.