Does your child mouth breathe, do you mouth breathe or know someone who does?

We know that finding information about mouth breathing and nasal obstruction can be difficult to find and we would like to help.

This mouth breathing and nasal obstruction blog post was written by a an ear, nose and throat surgeon who has performed thousands of flexible fiber optic evaluations of the upper airway which includes evaluation of the nose and nasal cavity structures.

As part of the background for this blog post, we searched the internet for frequently asked questions and answered them.

The goal of the blog post is to educate you on mouth breathing, why it occurs, what can block the nasal airway and can also lead to nasal congestion.

Additionally, the goal is to provide information about what the relationship is between mouth breathing and nasal congestion with snoring and obstructive sleep apnea.

This blog post provides illustrations that helps to explain the different areas of the nose that can cause nasal obstruction, which can lead to mouth breathing.

Airflow through the mouth before an adenoidectomy.
Airflow through the mouth before an adenoidectomy.

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Mouth breathing is a common problem in children and adults. Generally, mouth breathing occurs because the patient cannot breathe well through their nose (known as nasal obstruction).

Nasal obstruction can occur at many locations throughout the nose (external nose, dynamic collapse of the nostrils, deviated nasal septum, inferior turbinate hypertrophy, nasolacrimal duct cysts, nasal polyps, choanal atresia, adenoid hypertrophy, and growths in the nose (intranasal or nasopharyngeal masses)).

In children, large adenoids are a common cause for nasal obstruction. In adults, a deviated nasal septum and large inferior turbinates are common causes for nasal obstruction.

Treatment for nasal obstruction varies depending on the site of obstruction, but most often medications are tried and if the patient does not improve, then surgery may be recommended.

Common surgeries to treat nasal obstruction include rhinoplasty, septoplasty, turbinoplasty, nasal polypectomy, and adenoidectomy.

What causes mouth breathing?

Nasal breathing is the primary way that people breathe 92% of the time during wakefulness and 96% of the time during sleep.[1]

Nasal obstruction and mouth breathing go hand in hand.

Patients who have mouth breathing most often do so because the nose is blocked.

Upper airway with the black arrow pointing to the adenoids (which are enlarged).
Upper airway with the black arrow pointing to the adenoids (which are enlarged).

A study found that if mouth breathing is treated early, then the negative effects on the teeth and facial structures can be either averted or reduced.[2]

Everyone has had nasal obstruction at some point in time. For example, if you have a cold, then the nose is going to become obstructed.

A cold causes temporary nasal obstruction.

There are many causes of chronic nasal obstruction, they include:

  • Trauma to the external nose,
  • Weak nostrils that allow for dynamic collapse,
  • Deviated nasal septums,
  • Inferior turbinate hypertrophy,
  • Nasolacrimal duct cysts,
  • Nasal polyps,
  • Choanal atresia,
  • Adenoid hypertrophy, and
  • Growths in the nose (intranasal or nasopharyngeal masses).
Airway blockage before adenoidectomy, note that some air might get through, but sometimes the children can breathe through their noses.
Airway blockage before adenoidectomy, note that some air might get through, but sometimes the children can breathe through their noses.

How common is nasal obstruction?

Nasal obstruction has been reported to affect up to 40% of the population.[3]

How common is mouth breathing?

How do you diagnose the cause of mouth breathing?

Mouth breathing has a negative effect on the quality of life.

Eating becomes difficult because it is difficult to breathe through the nose when the mouth is full, so often children with nasal obstruction will open their mouths while eating in order to breathe.

What is the anatomy and physiology behind mouth breathing?


There is a difference in the presentation of nasal obstruction between children and adults.

Even within children, there are early and late presentations.

Early presentation is immediately after birth.

Children with nasal obstruction and forced mouth breathing immediately after birth may have congenital abnormalities, such as:

  • Nasolacrimal duct cysts,
  • A deviated septum from birth trauma,
  • An intranasal mass,
  • A nasopharyngeal mass (such as a dermoid), or
  • Choanal atresia.

Children with early presentations of nasal obstruction tend to undergo surgery for many reasons. First, newborns are obligate nasal breathers, so it is a real problem when a child cannot breathe through their nose. Second, if there is a mass in the nose, removal will allow for pathologists to diagnose the cause.

Late presentations of nasal obstruction and mouth breathing include:

  • Inferior turbinate hypertrophy,
  • Nasal polyps, and
  • Adenoid hypertrophy.

The late presentations of nasal obstruction are often associated with environmental allergies and inflammation or swelling of the tissues in the nose (nasal cavity tissues) and the back of the nose (nasopharynx).

Morais-Almeida and colleagues reviewed the literature for children and found that enlargement of the tonsils and adenoids and poorly controlled allergies were the two main causes of mouth breathing. [4]

Adults, on the other hand, tend to have acquired nasal obstruction.

Trauma can cause a deviated external nose and a deviated nasal septum.

Environmental allergies and the associated allergic rhinitis can trigger nasal obstruction.

Common sites for nasal obstruction in adults includes:

  • External nasal deformity (that causes internal narrowing of the nose),
  • Deviated nasal septum,
  • Inferior turbinate hypertrophy,
  • Nasal polyps (i.e. chronic sinusitis),
  • Adenoid hypertrophy.

Is there an age at which children do better with regard to their oral posture with respect to having nasal obstruction?

It has been shown that by age 8, if a child’s nasal obstruction has not been treated and they are mouth breathers, then they won’t do as well with regard to posture changes.[5]


Tests to evaluate the site of nasal obstruction include nasal endoscopy and imaging studies.

Nasal endoscopy is often the preferred initial way to evaluate the inside of the nose (nasal cavity) and the back part of the nose (nasopharynx) for causes of nasal obstruction. Usually, the person performing the nasal endoscopy is an ear, nose and throat surgeon, but other physicians may also perform nasal endoscopy.

Imaging studies to evaluate nasal obstruction can include:

  • Lateral cephalograms (usually in children with suspected adenoid hypertrophy),
  • CT (computed tomography) scans, and
  • MRI (magnetic resonance imaging) scans.
  • Acoustic rhinometry has also been used to evaluate the nasal resistance in the upper airway.[6]

Side Effects and Complications of No Treatment


Natural History

If an infection or seasonal allergies caused the nasal swelling, then the patient may get better once the infection clears or if the seasonal allergens are no longer around.

However, in most cases, observation doesn’t tend to improve nasal obstruction and therefore medical management and surgery are often explored.

Medical Management

Treatment for nasal obstruction can be in the form of medications and if there is not enough improvement, then surgery may be recommended.

Medications target the cause of the nasal obstruction.

Sinus rinses are designed by manufacturers and there is generally a bottle or a container that is designed to push water into one nostril in a manner that it rinses the surface and then comes out the other nostril or out the mouth.

Medications that treat allergies include:

  • Oral antihistamines (such as cetirizine (Zyrtec)),
  • Topical antihistamines include azelastine (Astelin),
  • Oral antileukotriene medications include montelukast (Singulair),
  • Topical steroids include mometasone (Nasonex) and fluticasone (Flonase), and
  • Oral steroids such as prednisone are sometimes prescribed for nasal polyps (chronic sinusitis).

A systematic review by Sun and colleagues found the Chinese herbal medicine has shown a good safety profile and had good clinical efficacy in reducing snoring, mouth breathing and nasal obstruction.[7]

However, the authors also stated that this needed to be confirmed by higher quality, randomized controlled trials.[7]

How well do nasal steroids work on reducing the size of the adenoids in children?

A review of the research found that mometasone (Nasonex) caused an improvement in nasal obstruction, adenoid size, snoring and quality of life.[8]

What happens when patients do not improve much after medical management? Is surgery performed?

Medical management can fail, and for those who fail, there is an option to see an ear, nose and throat surgeon.

There are several surgeries to treat nasal obstruction depending on the cause, common surgeries include:

  • Rhinoplasty,
  • Septoplasty,
  • Bilateral inferior turbinoplasty,
  • Nasal polypectomy, and
  • Adenoidectomy.

Does surgery to treat nasal obstruction result in an improvement in the long face and make it more normal in length?

The study found that there was a decrease in the facial length, but not always significantly; the average was about -0.76 mm.[9]

Frequently Asked Questions:

Can mouth breathing cause shortness of breath?

Mouth breathing in and of itself should not cause shortness of breath. Nasal breathing is preferred to mouth breathing in all people.

If someone cannot breathe through their nose, then the mouth provides a less obstructed way to breathe.

Can mouth breathing cause cavities or teeth damage?

Mouth breathing can dry the mouth. Saliva is produced in the mouth and having a dry mouth could contribute to cavities.

In preschool children, it has been shown that allergic rhinitis and oral breathing do affect oral health and teeth, with a higher rate of tooth loss, cavities of the teeth and oral fillings.[10]

A study evaluated patients with and without mouth breathing and found that those who breathe through their mouths during sleep have a decrease in the pH inside their mouths and this is thought to be a possible contributor to cavities and erosion of the teeth.[11]

Can mouth breathing cause crooked teeth?

Patients with mouth breathing tend to have nasal obstruction with a narrow and high arched palate.

A narrow and high arched palate can contribute to dental crowding, which is also known as crooked or overlapping teeth.

Dr. Fraga and colleagues reviewed the literature and found that the prevalence of Class 2 malocclusion tends to occur at a higher rate in children with mouth breathing when compared to children without mouth breathing.[12]

Can mouth breathing cause a sore throat?

It is possible that mouth breathing could contribute to a sore throat. Nasal breathing moistens or humidifies the air and also helps to warm the air so as the air travels down to the lungs it is at the humidity and temperature that is preferred for the lungs.

During mouth breathing, the air does not get as humidified as it does through the nose.

So, the air being breathed in is dryer and this can dry out the throat and in some people, this can cause a sore throat.

Can mouth breathing change your face?

Chronic mouth breathing leads to the patient having their mouth open during the day.

If the patient is a child and the face is still developing, then the effects of chronic mouth breathing are more prominent as the facial structure can change.

When the mouth is open, it stretches the soft tissues of the face to include the cheeks and the lips and there can also be changes to the bones of the face (upper and lower jaws).

In the extreme of cases, the child can develop Long Face Syndrome or Adenoid Faces, which are similar and overlapping syndromes.

In an adult, since the face is already done growing, there are fewer if any changes to the soft tissues and jaw.

Can mouth breathing be reversed?

Mouth breathing can be reversed in the far majority of patients.

Medical management should be attempted before surgery unless the patient had trauma that is unlikely to be improved with medications (for example, a patient with severe nasal trauma and their nose is very crooked).

Can mouth breathing cause oral thrush?

Oral thrush is an infection caused by yeast, specifically Candida albicans.

This can lead to white spots on the tongue and sometimes in other areas of the mouth, tongue and/or throat.

Dr. Surtel and colleagues found that mouth breathers have a higher frequencies of candida infections, bad breath (halitosis), gingivitis, periodontitis, and malocclusion.[13]

Can mouth breathing cause gas (belching or flatulence)?

Aerophagia is when air is taken in excessively and can lead to gas buildup. The body’s response to gas buildup is to release via belching and/or flatulence.

Although it cannot be generalized to humans, nasally obstructed rats had oral breathing and subsequent air swallowing (aerophagia).[14]

Another study described that rabbits, hamsters, guinea pigs, rats, and mice led to excessive accumulation of gas in the gastrointestinal tracts.[15]

Can mouth breathing cause an underbite?

Chronic nasal obstruction can lead to chronic mouth breathing.

It is possible that the chronic mouth breathing can lead to malocclusion of the teeth.

Chronic mouth breathing can lead to changes to the skeletal structure of the face. An extreme version of this is Long Face Syndrome and Adenoid Faces.

Can mouth breathing cause cough?

If the air is not as humidified and is not as filtered and not as warmed as the lungs would like, then could this lead to a cough?

This is a difficult question to answer because there are many, many variables that contribute to a cough.

A cough is created by the body in order to expel material or organisms from the lungs or airway.

Because patients with nasal congestion may have bad allergies, it is possible that the patients are having a reactive airway.

Allergies, asthma, and eczema are known to occur together as the allergic triad.

Therefore, a person with allergies may have problems with their lungs as well.

Treating allergies, and nasal obstruction could help improve symptoms coming from the lungs, such as a cough.

Government Disclaimer: The views expressed in this website are those of the author(s) and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the US Government.


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