Mouth breathing: causes, effects and when to see a GP

The nose normally filters, warms and moistens the air we breathe. Mouth breathing happens when airflow through the nose is limited and the mouth takes over, either all the time or during sleep. Most people do it temporarily during a cold or hay fever, and it usually stops when the nose clears.

It becomes a concern when it is persistent. The NHS does not describe mouth breathing as a condition in itself; it appears in its guidance as a feature of other problems such as a blocked nose, enlarged adenoids, snoring and a dry mouth. Working out why the nose is not carrying the airflow is the main task of assessment.

The NHS adenoidectomy page explains that adenoids are small lumps of tissue at the back of the throat behind the nose, which are part of the immune system. When they are enlarged they can partially block the airway, causing difficulty breathing through the nose, which can cause mouth breathing or snoring. They can also be linked with sleep apnoea, glue ear and frequent ear infections.

The NHS says the adenoids usually start to shrink around the age of 4 and disappear by early adulthood, and that a doctor might suggest waiting to see whether problems get better by themselves rather than operating, depending on how serious they are. Young children with sinusitis may also breathe through their mouth, according to the NHS, along with irritability and difficulty feeding.

The NHS lists several reasons for a blocked nose in people of any age. Hay fever, an allergic reaction to pollen, causes a runny or blocked nose, and the NHS says it can last for weeks or months, unlike a cold. Nasal polyps, which are painless soft growths inside the nose, can keep growing and block the nose, and the NHS says they cause a blocked or runny nose, reduced sense of smell or taste and snoring.

The NHS snoring page explains that snoring is caused by the tongue, mouth, throat or nasal airways vibrating as you breathe, because these parts relax and narrow when you are asleep. It lists a mouth that falls open when you are asleep and blocked or narrow airways in the nose as causes, and says you are more likely to snore if you are overweight, smoke, drink too much alcohol or sleep on your back.

• A cold or sinusitis, which can block the nose for a time.

• Hay fever or other allergic rhinitis.

• Nasal polyps.

• A structural narrowing of the nasal airway, which a GP or ENT specialist can assess.

The NHS says one of the main causes of a dry mouth is breathing through the mouth at night, which can happen if you have a blocked nose or sleep with your mouth open. A dry mouth makes you more likely to get tooth decay, the NHS says, so it is sensible to brush your teeth twice a day and use alcohol-free mouthwash.

Mouth breathing is also associated with snoring. The NHS says snoring is common and not usually caused by anything serious, but advises seeing a GP if it is having a big impact on your life or your partner's, or if you feel sleepy by day, your breathing stops and starts, or you gasp or choke in your sleep, which may be sleep apnoea and can be serious if untreated.

For adults, the NHS suggests seeing a GP if snoring does not improve with lifestyle changes, if it has a big impact, or if there are signs of sleep apnoea. For a dry mouth, it advises seeing a GP if it makes it difficult to talk or eat, is still dry after a few weeks of home or pharmacy treatments, or comes with a sore, red, swollen or bleeding mouth or white patches.

For children, persistent mouth breathing with snoring, disturbed sleep, repeated ear infections or hearing problems is worth discussing with a GP. The NHS says that doctors may suggest waiting if enlarged adenoids are causing only mild problems, and that an adenoidectomy is mainly done in children.

For nasal polyps, the NHS says to see a GP if you have difficulty breathing, your symptoms are getting worse or you notice changes to your sense of smell. For hay fever, see a GP if symptoms are getting worse or do not improve after pharmacy medicines.

Treatment depends on the cause. The NHS suggests that for blocked or narrow nasal airways, nasal dilators or strips, decongestants or nasal sprays may help, and that a chin strap or a device that makes you breathe through your nose may be used for a mouth that falls open in sleep. For a dry mouth it recommends regular sips of cold water, sugar-free gum or sweets, and asking a pharmacist about gels, sprays or lozenges.

Hay fever is managed with antihistamines or steroid nasal sprays from a pharmacy or GP, according to the NHS, and nasal polyps are usually treated with steroid nose drops or a spray, with surgery if there is no improvement after about 12 weeks. A saline rinse can help unblock the nose, although the NHS says salt water washes are not suitable for children.

The NHS says an adenoidectomy usually takes about 30 minutes, is done under general anaesthetic as a day case, and recovery takes about a week. It says complications are rare.

On the NHS, assessment starts with a GP, who can look in the nose and mouth and refer to ear, nose and throat (ENT) services if needed. A pharmacist can advise on decongestants and sprays for short-term blockage.

Private ENT clinics offer quicker appointments and nasal assessment, and the options discussed are the same. The NHS notes that surgery for snoring is not widely available on the NHS and does not always work, so it is worth understanding the evidence for any procedure before choosing it.