Summary for mouth breathing in children:

Mouth breathing is a common problem in children, especially if they have allergies (allergic rhinitis) or a cold (upper respiratory infection).

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 in kids such as large inferior turbinate, cysts (nasolacrimal duct cysts), nasal polyps, partial physical blockage (choanal atresia), and large adenoids (adenoid hypertrophy).

In children, large adenoids are a common cause of chronic nasal obstruction.

Treatment for chronic 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.

Two common surgeries to treat nasal obstruction in children include inferior turbinoplasty and adenoidectomy.

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

Introduction for mouth breathing in children:

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.

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

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 or allergies, then the nose can become obstructed.

The common cold and allergies tend to cause nasal obstruction for a short time.

Once the cold has resolved, the swelling tends to decrease.

When allergies are treated, or the allergen is no longer around (i.e. grass, pollen, specific food), then the swelling in the nose tends to decrease.

If the swelling in the nose is a persistent problem, then the child may develop chronic nasal obstruction.

What are the causes of chronic nasal obstruction in kids?

Causes of nasal obstruction and mouth breathing include:

  • inferior turbinate hypertrophy;
  • nasolacrimal duct cysts;
  • nasal polyps;
  • choanal atresia; and
  • adenoid hypertrophy.
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.

Diagnosis, Symptoms

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.


There are early and late presentations for mouth breathing.

The early presentation is immediately or shortly after birth and can include:

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

  • an infectious process (such as a virus or bacterial infection);
  • a cyst inside the nose (nasolacrimal duct cysts);
  • a deviated septum from birth trauma;
  • a growth (mass) inside the nose;
  • a growth or mass in the back of the nose (nasopharyngeal mass such as a dermoid); and
  • choanal atresia.

Children with early presentations of nasal obstruction tend to undergo surgery for many reasons.

First, newborns are obligate nasal breathers, which means that they will try over and over to breathe through their nose only.

So it is a real problem when a child cannot breathe through their nose.

Second, if there is a mass in the nose, then the removal will allow for pathologists to diagnose what it is.

Late presentations of nasal obstruction and mouth breathing include:

  • a foreign body (usually these children present with foul-smelling drainage from one nostril);
  • swelling of tissues in the nose (inferior turbinate hypertrophy);
  • polyps (nasal polyps also known as chronic sinusitis); 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. 3

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 keeping their mouths open even if they can breathe well through their nose (oral posture changes).4


What tests help determine the cause of nasal obstruction?

The healthcare provider might order allergy testing and may take cultures of the drainage from the nose.

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.

Nasal endoscopy in a girl with large adenoids. Note the scope goes into the nose and the image can be seen on the screen or viewer depending on the type of scope.
Nasal endoscopy in a girl with large adenoids. Note the scope goes into the nose and the image can be seen on the screen or viewer depending on the type of scope.

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:

  • x-rays (lateral cephalograms which are usually reserved for children with suspected adenoid hypertrophy);
  • CT (computed tomography) scans; and
  • MRI (magnetic resonance imaging) scans.

The Natural History of Observation:

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.

If the cause is a foreign body (i.e. tissue paper, small pieces of food, or toys that the child has placed into their nose), then the foul-smelling drainage tends to persist until it is removed.

So, if observation doesn’t tend to improve nasal obstruction then medical management and surgery are often explored.

What is the Medical Management for Nasal Obstruction?

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. Distilled water needs to be used and directions need to be followed.

What medications treat allergies?

  • oral antihistamines (such as cetirizine);
  • topical antihistamines include azelastine;
  • oral anti-leukotriene medications include montelukast;
  • topical steroids include mometasone and fluticasone; and
  • oral steroids such as prednisone are sometimes prescribed for nasal polyps (chronic sinusitis) or persistent swelling of tissue.

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.5

What Surgeries help treat Nasal Obstruction in Children?

  • adenoidectomy;
  • inferior turbinoplasty;
  • removal of the foreign body; and/or
  • targeted surgeries for other sites of obstruction.
Remnant adenoid tissue after adenoidectomy. The adenoid tissue is shown with the blue arrow pointing to it.
Remnant adenoid tissue after adenoidectomy. The adenoid tissue is shown with the blue arrow pointing to it.

Frequently Asked Questions:

Can mouth breathing cause shortness of breath?

Mouth breathing in and of itself should not cause shortness of breath during the daytime in older children.

Newborns breathe through their nose primarily, so in their case, they may have significant trouble breathing through their mouths.

In newborns and older children, nasal obstruction can force them to breathe through their mouths, which can lead to snoring and/or obstructive sleep apnea in some children.

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.6

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.7

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.8

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

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 higher frequencies of candida infections, bad breath (halitosis), gingivitis, periodontitis, and malocclusion.9

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).10

Another study described that rabbits, hamsters, guinea pigs, rats, and mice led to excessive accumulation of gas in the gastrointestinal tracts. 11

Can mouth breathing cause an underbite?

Chronic nasal obstruction can lead to chronic mouth breathing.

It is possible that 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.


1.            Fitzpatrick MF, McLean H, Urton AM, Tan A, O’Donnell D, Driver HS. Effect of nasal or oral breathing route on upper airway resistance during sleep. Eur Respir J. 2003;22(5):827-832.

2.            Jefferson Y. Mouth breathing: adverse effects on facial growth, health, academics, and behavior. Gen Dent. 2010;58(1):18-25; quiz 26-17, 79-80.

3.            Morais-Almeida M, Wandalsen GF, Sole D. Growth and mouth breathers. J Pediatr (Rio J). 2019.

4.            Krakauer LH, Guilherme A. Relationship between mouth breathing and postural alterations of children: a descriptive analysis. Int J Orofacial Myology. 2000;26:13-23.

5.            Chohan A, Lal A, Chohan K, Chakravarti A, Gomber S. Systematic review and meta-analysis of randomized controlled trials on the role of mometasone in adenoid hypertrophy in children. Int J Pediatr Otorhinolaryngol. 2015;79(10):1599-1608.

6.            Bakhshaee M, Ashtiani SJ, Hossainzadeh M, Sehatbakhsh S, Najafi MN, Salehi M. Allergic rhinitis and dental caries in preschool children. Dent Res J (Isfahan). 2017;14(6):376-381.

7.            Choi JE, Waddell JN, Lyons KM, Kieser JA. Intraoral pH and temperature during sleep with and without mouth breathing. J Oral Rehabil. 2016;43(5):356-363.

8.            Fraga WS, Seixas VM, Santos JC, Paranhos LR, Cesar CP. Mouth breathing in children and its impact in dental malocclusion: a systematic review of observational studies. Minerva Stomatol. 2018;67(3):129-138.

9.            Surtel A, Klepacz R, Wysokinska-Miszczuk J. [The influence of breathing mode on the oral cavity]. Pol Merkur Lekarski. 2015;39(234):405-407.

10.          Erkan M, Erhan E, Saglam A, Arslan S. Compensatory mechanisms in rats with nasal obstructions. Tokai J Exp Clin Med. 1994;19(1-2):67-71.

11.          Nakajima K, Ohi G. Aerophagia induced by the nasal obstruction on experimental animals. Jikken Dobutsu. 1977;26(2):149-159.