Post-nasal drip: causes, treatment and how long it lasts

There is no single treatment, because post-nasal drip is a symptom, and the right approach depends on the cause. The NHS says that catarrh usually goes away by itself and that phlegm and mucus are not harmful but are the body's way of clearing infection. Self-care aims to loosen mucus and keep the nose and throat comfortable.

If a pharmacist or GP is involved, the NHS says a pharmacist can advise on decongestants and other medicines to relieve catarrh, and on salt water nose rinses, and that a GP may suggest the same treatments. For sinusitis, a doctor may prescribe steroid nasal sprays or drops, sometimes for a few months, and antihistamines if an allergy is the cause. The NHS says antibiotics are rarely needed because sinusitis is usually caused by a virus rather than bacteria.

The NHS suggests a handful of simple measures for catarrh: drink plenty of water, sip ice-cold water when you need to clear your throat rather than coughing or swallowing, use a humidifier or sit in the bathroom with a hot shower running to loosen mucus, gargle with salt water and rinse your nose with salt water. It adds that mucus is not harmful and that catarrh usually goes away by itself.

The NHS gives a method for a homemade rinse: boil a pint of water and let it cool, mix in 1 teaspoon of salt and 1 teaspoon of bicarbonate of soda, wash your hands, stand over a sink and sniff a small amount into one nostril at a time, breathing through your mouth and letting the water pour back out, up to 3 times a day. A fresh solution should be made each day. For nasal polyps it notes salt water washes are not suitable for children.

For sinusitis, the NHS also suggests rest, plenty of fluids, painkillers such as paracetamol or ibuprofen, avoiding allergy triggers and not smoking. If you have a high temperature or do not feel well enough for normal activities, it advises staying at home and avoiding contact with others until you feel better.

According to the NHS, catarrh symptoms can include a constantly blocked or runny nose, a feeling that there is a lump or something stuck in the throat, a frequent need to swallow or cough to clear the throat, the sense of mucus dripping down the back of the throat and a crackling feeling in the ears. These symptoms usually only last a few days, but sometimes they can last longer.

If sinusitis is the cause, the NHS lists pain, swelling and tenderness around the cheeks, eyes or forehead, a blocked or runny nose, a reduced sense of smell, green or yellow mucus from the nose and a high temperature. Nasal polyps, which are painless soft growths inside the nose, can cause a blocked or runny nose, post-nasal drip, a reduced sense of smell or taste and snoring, and the NHS notes that they can feel like a cold but will not get better unless treated.

Everybody makes mucus in the nose and sinuses all the time, but when the lining becomes swollen it makes more than usual. The NHS describes catarrh as a build-up of mucus in your nose and sinuses and phlegm in your throat, and lists the sensation of mucus slowly dripping down the back of the throat (postnasal drip) as one of its symptoms. It is the same experience many people call post-nasal drip: a sticky, annoying trickle that makes you want to clear your throat or swallow repeatedly.

Because it is a symptom rather than a diagnosis, the useful question is what is making the nose and sinuses produce or retain extra mucus. The sources used for this guide point towards infections, irritants, allergy and structural problems inside the nose.

The NHS describes catarrh as the body's natural reaction to things like infection: the lining of the nose, sinuses and throat becomes swollen and creates more mucus than normal. The causes it lists are infections such as a cold, flu and sinusitis, pollution and cigarette smoke, allergic reactions to things like pollen, dust and animals, and conditions that affect the nose, such as nasal polyps.

Sinusitis is swelling of the sinuses, usually caused by an infection, and the NHS says it is common after a cold or flu and usually clears up on its own within 4 weeks. Because the swelling stops mucus draining properly into the nose and throat, people feel blocked up. For nasal polyps, the NHS says it is not clear what causes them, though asthma and an intolerance or sensitivity to aspirin can increase the risk.

It depends on the cause. The NHS says catarrh symptoms usually only last a few days, but sometimes they can last longer, and advises seeing a GP if you have the symptoms for more than a few weeks.

The NHS says a cold usually gets better within 1 to 2 weeks, sinusitis usually clears up on its own within 4 weeks, and hay fever can last for weeks or months. Nasal polyps, by contrast, will not get better unless treated, the NHS says, so persistent symptoms deserve a check.

Post-nasal drip itself is a symptom, so it is not something you catch. What matters is the cause. The NHS says colds are caused by viruses and easily spread to other people, that you are infectious until all your symptoms have gone, which usually takes 1 to 2 weeks, and that colds are spread by germs from coughs and sneezes which can live on hands and surfaces for 24 hours.

Hay fever is an allergic reaction to pollen, according to the NHS, and catarrh from smoke or pollution is a reaction to irritants. If you have a high temperature or do not feel well enough to do normal activities, the NHS advises staying at home and avoiding contact with other people until you feel better.

A pharmacist can help with catarrh, the NHS says, including decongestants and other medicines to relieve it, and salt water nose rinses in the form of specially designed bottles, nasal sprays and sachets. For sinusitis a pharmacist can give the same treatments as a GP and can direct you to other help if needed.

The NHS says to see a GP if sinusitis symptoms do not improve after 7 days of treatment from a pharmacy or GP, if they do not get better after 3 weeks of treating symptoms yourself, if you keep getting sinusitis, or if the person is a child aged 11 or younger. Treatment from a doctor may include steroid nasal sprays or drops, sometimes for a few months, and antihistamines if allergy is involved. Antibiotics are rarely needed because sinusitis is usually caused by a virus.

A GP may refer you to an ear, nose and throat (ENT) specialist if you still have sinusitis after 3 months of treatment, keep getting it or only have symptoms on one side of your face, according to the NHS. For nasal polyps, a GP can usually see them by looking inside the nose, steroid drops or sprays are the usual treatment, and surgery may be suggested if there is no improvement after about 12 weeks, though polyps commonly grow back within a few years.

Persistent symptoms need review rather than indefinite self-treatment. The NHS says to see a GP if catarrh lasts more than a few weeks or if you develop a sore throat, problems swallowing or loss of sense of smell, because the GP may want to rule out other conditions such as nasal polyps. With nasal polyps, see a GP if you have difficulty breathing, symptoms are getting worse or you notice changes in your sense of smell.

For sinusitis, the NHS says to ask for an urgent GP appointment or get help from NHS 111 if you are very unwell, if painkillers do not help or symptoms get worse, or if you have a weakened immune system, for example because of chemotherapy.

On the NHS, a community pharmacist is a sensible first step for catarrh, as the NHS notes, and a GP can look inside the nose and arrange treatment or an ENT referral if symptoms persist. Urgent concerns go through NHS 111, as described above.

Some people choose to see a private ENT specialist, for example for persistent one-sided symptoms or suspected polyps. If you do, share any findings with your NHS GP so your treatment plan stays consistent, and still use the red-flag advice above if new symptoms such as problems swallowing appear.