Nasal polyps are abnormal tissue growths that grow inside the nasal passages and sinuses.
The sinuses are small spaces on either side of the nose behind the cheekbones, eyes and forehead.
Nasal polyps vary in size and can be yellowish, grey or pink in colour. Each polyp is shaped like a teardrop, and they look like grapes on a stem when they are fully grown. Large nasal polyps can block the nasal passage and cause symptoms such as:
- a blocked or runny nose
- a loss of smell and taste
These symptoms of nasal polyps are also associated with many other conditions, including the common cold. However, colds usually clear up within 2 to 14 days, whereas nasal polyps don't go away without treatment. See your GP if you have cold-like symptoms that last for more than two weeks.
If polyps develop in or near the sinuses, they may cause a sinus infection that leads to pain and tenderness in the face.
Nasal polyps are not cancerous and do not increase your risk of developing nasal cancer in the future.
What causes nasal polyps?
The exact cause of nasal polyps is unknown. They appear to be the result of constant inflammation (redness and swelling) that develops inside the lining of the nasal passageways, known as the mucus membrane. It is unclear what triggers the inflammation.
Several factors increase your risk of developing nasal polyps. These include:
- allergic rhinitis
- - a condition where substances, such as dust mites or animal fur, cause cold-like symptoms such as sneezing
- cystic fibrosis - a condition where the lungs and digestive system become clogged up with a sticky fluid
- aspirin intolerance - where you experience allergic-like symptoms, such as itchy skin and persistent coughing, if you take the painkiller aspirin (some people with an aspirin intolerance also have a similar reaction to other painkillers, such as ibuprofen)
Treating nasal polyps
Nasal polyps can be treated with steroid medication (corticosteroids) that help shrink the polyps.
Corticosteroids can be prescribed either as a short course of steroid tablets or in the form of a nasal spray.
Surgery is sometimes recommended for larger polyps that don't respond to medication. Two types of surgery can be used:
- endoscopic sinus surgery, where the surgeon removes the polyps using either surgical instruments or a laser
- a polypectomy, which involves removing the polyps using a wire loop or forceps
Nasal polyps are usually easily treated, although it is quite common for them to grow back. This often happens a few months after treatment with medication or about two to three years after surgery. People with other long-term conditions, such as asthma, are more likely to have recurring polyps.
Read more about treating nasal polyps.
Who gets nasal polyps?
It is difficult to estimate exactly how common nasal polyps are because smaller polyps that do not cause any symptoms may go undetected. However, one study estimated that around 1% of people will have nasal polyps at some point in their life.
Polyps are four times more common in men than in women and they usually affect adults who are 40 years of age or over. In children, polyps are much rarer, usually only affecting children with cystic fibrosis.
Nasal polyps only usually cause symptoms if an individual polyp is particularly large or if you have clusters of polyps.
The symptoms of polyps can include:
- a blocked nose, which may cause breathing difficulties meaning you have to breathe through your mouth
- a runny nose
- mucus that drips from the back of your nose down your throat, which is known as post-nasal drip
- a reduced sense of smell or taste - in severe cases, you may totally lose your sense of smell or taste
If one or more polyps develop in or around one of your sinuses, fluid and mucus can build up inside your sinus. Sinuses are the air-filled cavities located on each side of your nose. This produces an ideal environment for infection to develop.
A sinus infection is known as sinusitis. Symptoms of sinusitis include:
- facial pain and tenderness near the infected sinuses, which is usually a throbbing pain that feels worse when you move your head and toothache or pain in your jaw when you eat
- a high temperature of 38C (100.4F) or above
Some people with nasal polyps develop repeated bouts of sinusitis.
More serious conditions
Occasionally, a single, very large polyp or a large cluster of smaller polyps can cause more serious problems.
Obstructive sleep apnoea
A very large polyp or a group of polyps can temporarily block your airways while you are sleeping. This condition is called obstructive sleep apnoea (OSA).
Most people are unaware that they have breathing difficulties during the night because the condition does not cause you to wake up fully. However, constant interruptions to sleep mean that you feel very sleepy during the day.
Double vision is another potentially serious condition that can be caused by a large polyp or cluster of polyps.
The polyps can disrupt the normal workings of nerves and muscles that control your eyes. This means your eyes no longer work together and you see two images of a single object.
When to get medical help
A blocked or runny nose and a reduced sense of smell are typical symptoms of nasal polyps. However, they are also related to many other conditions, including the common cold. Colds usually clear up within 2 to 14 days, but nasal polyps do not get better without treatment.
See your GP if you have cold-like symptoms that last for more than two weeks.
Is it just a cold?
A stuffy, runny nose and reduced sense of smell are the typical symptoms of nasal polyps, but they may also be the signs of many other conditions, including the common cold.
Colds usually clear up in two to 14 days, while nasal polyps do not go away on their own. See your GP if you have these symptoms for more than two weeks.
It is thought that nasal polyps occur as a result of the inflammation (swelling) in the lining of the nasal cavities and sinuses, called the mucus membrane.
Inflammation causes fluid to build up in the cells of the mucus membrane. Over time, gravity pulls on the fluid-filled cells and causes them to develop into polyps.
Exactly what triggers the process of inflammation inside the nasal cavities is unclear. However, several theories have been suggested including:
- The inflammation is a response to a bacterial, viral or fungal infection.
- The inflammation is an allergic-like reaction, for example to pollution.
- Certain genes that a person inherits from their parents make them more likely to develop nasal polyps.
- Problems with the nervous system disrupt the normal flow of fluid through the lining of the nose, leading to inflammation.
- The immune system (the body's natural defence against illness and infection) goes wrong in some way and begins to attack the tissues of the lining of the nose, causing it to become inflamed.
It's possible that a combination of these factors could be responsible for nasal polyps.
While the exact causes of nasal polyps are unknown, several factors increase your risk of developing them. These include:
- asthma that starts in adulthood - 20-40% of people with nasal polyps also have asthma
- allergic rhinitis - where a person develops cold-like symptoms due to an allergic reaction
- cystic fibrosis - where the lungs and digestive system become clogged with a sticky fluid (about 25% people with cystic fibrosis develop nasal polyps)
- having an intolerance to aspirin
- Churg-Strauss syndrome - a rare condition that causes inflammation of the blood vessels
It is likely that your GP will ask you about your symptoms and carry out a physical examination of your nostrils.
Nasal polyps near the openings of your nostrils may be easy to see by simply shining a light up your nose. However, further tests may be needed to locate polyps that are further up your nasal passageways or in one of your sinuses.
If further testing is required, it will usually be carried out at the ear, nose and throat (ENT) department of your local hospital.
A diagnosis of nasal polyps can usually be confirmed by carrying out a computerised tomography (CT) scan of your nasal passageways and sinuses. A CT scan involves taking a series of X-rays and then using a computer to assemble them into a more detailed image.
Polyps will usually show up as distinctive bulges in the walls of your nasal passageways and sinuses.
If it is thought that an allergy may be contributing to your symptoms, you may be referred for an allergy skin prick test. This involves pricking your skin with tiny amounts of substances known to be common causes of allergies to see if your skin reacts.
Nasal polyps are not usually found in children, with the exception of children who have cystic fibrosis. Therefore, if your child develops nasal polyps, it is usually recommended that they are tested for cystic fibrosis as a precaution.
A widely used test for cystic fibrosis involves measuring the amount of salt in a sample of sweat. An unusually high amount of salt may be due to cystic fibrosis.
Read more about diagnosing cystic fibrosis.
Steroid sprays and drops
If you have one or more small polyps, your GP may prescribe a nasal spray or nose drops that contain steroid medicine (topical corticosteroids). These can help reduce the inflammation in your nose and shrink your polyps.
A type of spray called mometasone is usually recommended because it is known to cause fewer side effects than other steroid sprays. The recommended dose is usually two sprays into each nostril once a day.
Most people do not have any side effects after using mometasone. However, where side effects occur, the most commonly reported ones are:
It can take five weeks of using a nasal spray before the symptoms of nasal polyps get better. If you still have symptoms after this time, see your GP or the specialist in charge of your care. You may require additional treatment.
If you have large polyps or if your symptoms are particularly troublesome, your doctor may prescribe a short course of steroid tablets (oral corticosteroids), either alone or in combination with a nasal spray.
A type of steroid medication called prednisone is usually recommended. It is likely that you will be prescribed no more than three weeks worth of prednisone. This is because using the medication for longer than this increases your risk of developing side effects, such as:
If your symptoms do not improve after three weeks, you may need to have surgery to remove the polyps.
Surgery to remove nasal polyps may be recommended if:
- your symptoms don't respond to treatment with steroids
- you have repeated episodes of nasal polyps despite treatment with steroids
- you have developed a more serious secondary condition due to the polyps, such as obstructive sleep apnoea or double vision
Endoscopic sinus surgery
A type surgery called endoscopic sinus surgery is usually recommended to remove nasal polyps.
The procedure is usually carried out under local anaesthetic (painkilling medication) so that the tissue of the nose is numb throughout the procedure.
The surgeon will use an endoscope (a thin, flexible tube with a video camera at one end) to see inside your nose and sinuses. They will make small cuts to your face and insert surgical instruments to open the sinus cavities and remove the polyps. Alternatively, some surgeons now use a laser to burn away the polyps.
Once the surgery is complete, a dressing is placed inside your nostrils to stem any bleeding. The dressing can be removed one to two days after surgery. Most people can return home on the same day as the surgery, but it may take one to two weeks before you can start doing your normal daily activities again.
Your surgeon can give you more detailed information and advice.
The most common complications of endoscopic sinus surgery are:
- infection at the site of the surgery
- persistent nosebleeds
An infection can usually be successfully treated with antibiotics. If you have persistent nosebleeds, contact your surgical team because you may need to go back to hospital for further treatment.
Endoscopic sinus surgery has a good track record of success with around 90% of people reporting a marked improvement in their symptoms. However, in around 8% of cases, the polyps grow back after two to three years.
If you have smaller polyps that are near the opening of your nostrils and are easily accessible, an alternative surgical technique called a polypectomy may be recommended.
A polypectomy involves holding your nose open with a small surgical clamp and cutting away the polyps with a loop of wire or forceps. A dressing is then applied to stem any bleeding.
A polypectomy is usually carried out under general anaesthetic, which means that you will be asleep during the procedure and will not feel any pain. You should be able to leave hospital after you have recovered from the effects of the anaesthetic.
It is common for dry blood that develops inside your nose after surgery to cause an obstruction. However, this should clear within a few weeks.
You may have nosebleeds for the first few days after surgery. It is also common for small amounts of blood to come out of your nose when you blow it. This can occur for around a month after surgery. Avoid smoking for the first two weeks after surgery because it will irritate your nose.
As with endoscopic sinus surgery, an infection is the most common complication after a polypectomy.
The results of a polypectomy are similar to those of endoscopic sinus surgery. However, the chance of the polyps growing back after a polypectomy is much higher (it's estimated that they will return in about a third of people).
If you have recurring nasal polyps, or if you have a condition such as asthma, hayfever or a long-term sinus infection that makes it likely that you will develop polyps, you may need to use a daily steroid nasal spray to help prevent your nose becoming inflamed.