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Causes courantes de la mauvaise haleine

Dans cette série :Halitose

La plupart des cas de mauvaise haleine (halitose) proviennent de germes (bactéries) ou de débris qui s'accumulent dans la bouche.

En un coup d'œil

  • Most people have bad breath after sleeping due to a dry mouth.

  • Certain foods, drinks, and medicines can cause temporary bad breath.

  • Smoking and some diets, like low-carbohydrate plans, can cause bad breath.

  • Poor oral hygiene, including food stuck between teeth, plaque, and gum disease, is a common cause.

  • A coating on the tongue or tonsil stones can also lead to bad breath.

  • If you have bad breath and other symptoms, it could indicate another medical condition.

What causes bad breath?

Morning bad breath

Most people have some degree of bad breath after a night's sleep. This is normal and occurs because the mouth tends to get dry and stagnate overnight. This usually clears when the flow of saliva increases soon after starting to eat breakfast.

Dry mouth (xerostomia)

Bad breath associated with a bouche sèche is caused by a reduction in the cleansing mechanism of the mouth as a result of reduced flow of saliva from the salivary glands. There are many causes of a dry mouth contributing to bad breath. The most common cause is after a night's sleep (discussed above). Dry mouth may also occur:

Artificial saliva is available; all can be bought over the counter at pharmacies and some can be prescribed on the NHS for certain conditions.

Foods, drinks and medicines

Chemicals in foods can get into the bloodstream and then be breathed out from the lungs. Most people are familiar with the smell of garlic, spicy foods and alcoholic drinks on the breath of people who have recently eaten or drunk these. Various other foods and medicines can cause bad breath. This type of bad breath is temporary and easily cured by not eating the food.

If a medicine is the cause of bad breath, then discuss possible alternatives with your doctor. Medicines that have been associated with bad breath include:

  • Betel.

  • Chloral hydrate.

  • Nitrites and nitrates.

  • Dimethyl sulfoxide.

  • Disulfirame.

  • Some chemotherapy medicines.

  • Phenothiazines.

  • Amfetamines.

  • Lithium.

  • 'Water' tablets (diuretics).

  • Bisphosphonates.

Check the list of side-effects on the leaflet that comes with your medicine if you think it might be causing bad breath.

Tabagisme

Most non-smokers can tell if a person is a smoker by their breath. . Stopping smoking is the only cure for this type of bad breath. Smoking tobacco products also increases the risk of developing les maladies des gencives - another cause of bad breath.

Diets

Crash dieting or fasting can cause a sickly sweet smell on the breath. This is due to chemicals called ketones being made by the breakdown of fat. Some ketones are then breathed out with each breath. Low-carbohydrate and keto diets also can cause this sort of bad breath.

Medical causes

Medical causes, other than health problems in the mouth, are relatively uncommon. Possible causes include:

  • Nasal problems. For example, a lump (polyp) in the nose or a small object stuck in a nostril (occurs most commonly in children) can cause a bad smell. In this situation, the smell tends to occur only, or more severely, when you breathe out through your nose. It is not so noticeable when you breathe out through your mouth.

  • Sinus infections.

  • Throat infections such as amygdalite.

  • Mouth infections, such as abcès dentaires.

  • Infections ou tumours of the lung.

  • Bronchectasie.

  • Reflux of acid from the stomach ou a stomach infection called Helicobacter pylori.

  • Diabète.

  • Severe kidney or liver problems.

  • Fish odour syndrome (trimethylaminuria). This is a rare medical cause but worth being aware of. It typically causes breath and body odour that is often like a fishy smell. It occurs because the body loses the ability to properly break down trimethylamine which is found in certain foods. There is then a build-up of trimethylamine in the body which is released in sweat, urine and breath. Urine and blood tests can help to confirm this diagnosis if it is suspected.

In these medical cases, there are usually other symptoms that would indicate the cause. For example, a blocked nose, sinus pain, chest symptoms, a high temperature (fever), etc. If you are otherwise well and have no other symptoms apart from bad breath, the smell is likely to be coming from a build-up of bacteria in the mouth and other medical causes are unlikely.

Bad breath caused by germs (halitosis)

In most people who have bad breath (halitose), the bad smell is thought to come from germs (bacteria) and debris within the mouth.

As the bacteria break down proteins and other debris in the mouth, they release foul-smelling gases. One or more of the following may contribute to the build-up of bacteria, debris and bad breath:

Food stuck between teeth and gums

Normal teeth brushing may not clear bits of food which can get stuck between teeth. The food then rots and becomes riddled with bacteria. In addition to regular cleaning with fluoride toothpaste, flossing between the teeth (or using interdental brushes) can clear and prevent this problem.

If you wear dentures, they should be removed and cleaned every night.

Plaque, tartar (calculus) and gum disease

Plaque dentaire is a soft whitish deposit that forms on the surface of teeth. It forms when bacteria combine with food and saliva. Plaque contains many types of bacteria. Calculus is hardened calcified plaque. It sticks firmly to teeth. Gum disease means infection or inflammation of the tissues that surround the teeth. If your gums look inflamed, or regularly bleed when you clean your teeth, you are likely to have gum disease. The severity can range from mild to severe.

There is some evidence that antibacterial mouthwashes (such as those containing chlorhexidine) may also be useful in preventing bad breath. Be aware that these may discolour your teeth or dentures. These can be bought over the counter.

Coating on the back of the tongue

In some people, a coating develops on the back part of the tongue. It is not clear why this occurs. It may be from mucus that drips down from the back of the nose (postnasal drip). The coating can contain many bacteria. This explains why bad breath can sometimes occur in people with otherwise good oral hygiene. It is recommended that the tongue is cleaned every night with a proper utensil (such as a tongue scraper), rather than a toothbrush.

Tonsil stones (tonsilloliths)

Calculs amygdaliens are are clusters of calcified material that form in the tonsillar crypts, or crevices of the tonsils. They are made up mostly of calcium but can contain other ingredients such as magnesium and phosphorus, and can feel like a small lump in the tonsils. Rarely harmful, they can be a nuisance and hard to remove and can often cause bad breath.

Questions fréquemment posées

Can bad breath caused by diet changes like a keto diet be permanent?

Bad breath resulting from diets like low-carbohydrate or keto diets, or from fasting, is due to the body breaking down fat and producing chemicals called ketones. This type of bad breath is usually temporary and would likely resolve if the diet is altered or stopped.

What is the best way to clean my tongue to prevent bad breath if I have a coating?

If you have a coating on the back of your tongue that contributes to bad breath, it is recommended to clean it every night. Using a proper utensil like a tongue scraper is more effective than using a toothbrush for this purpose.

Are there any specific symptoms that suggest my bad breath might be due to a serious underlying medical condition?

If bad breath is caused by a serious underlying medical condition, there are usually other noticeable symptoms in addition to the bad breath. These could include a blocked nose, sinus pain, chest symptoms, or a high temperature (fever). If you are generally well and only experience bad breath, it's less likely to be a serious medical issue.

Can using artificial saliva help with bad breath, and how do I get it?

Yes, artificial saliva can help with bad breath if it's caused by a dry mouth. A dry mouth reduces the mouth's natural cleansing action. Artificial saliva products are available for purchase over the counter at pharmacies, and some types can be prescribed on the NHS for specific medical conditions.

If I suspect my medicine is causing bad breath, what should I do?

If you believe a medicine is responsible for your bad breath, you should discuss possible alternative medications with your doctor. You can also check the leaflet that comes with your medicine to see if bad breath is listed as a potential side-effect.

Lectures complémentaires et références

  • Halitose; NICE CKS, septembre 2024 (accès réservé au Royaume-Uni)
  • Izidoro C, Botelho J, Machado V, et al; Revisiting Standard and Novel Therapeutic Approaches in Halitosis: A Review. Int J Environ Res Public Health. 2022 Sep 8;19(18). pii: ijerph191811303. doi: 10.3390/ijerph191811303.
  • Jamali Z, Alipour M, Ebrahimi S, et al; Effect of Halita mouthwash on oral halitosis treatment: A randomized triple-blind clinical trial. J Dent Res Dent Clin Dent Prospects. 2019 Winter;13(1):31-35. Epub 2019 Apr 24.
  • Acar B, Berker E, Tan C, et al; Effects of oral prophylaxis including tongue cleaning on halitosis and gingival inflammation in gingivitis patients-a randomized controlled clinical trial. Clin Oral Investig. 2019 Apr;23(4):1829-1836. doi: 10.1007/s00784-018-2617-5. Epub 2018 Sep 13.
  • Poniewierka E, Pleskacz M, Luc-Pleskacz N, et al; Halitosis as a symptom of gastroenterological diseases. Prz Gastroenterol. 2022;17(1):17-20. doi: 10.5114/pg.2022.114593. Epub 2022 Mar 18.
  • Kauss AR, Antunes M, Zanetti F, et al; Influence of tobacco smoking on the development of halitosis. Toxicol Rep. 2022 Mar 6;9:316-322. doi: 10.1016/j.toxrep.2022.02.012. eCollection 2022.

À propos de l'auteurVoir la biographie complète

Image de l'auteur

Dr Mary Harding, MRCGP

Médecin généraliste, Auteur médical

BA, MA, MB, BChir, MRCGP, DFFP

Le Dr Mary Harding a obtenu son diplôme de l'école de médecine de l'Université de Cambridge en 1989.

À propos du critiqueVoir la biographie complète

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Dr Krishna Vakharia, MRCGP

Médecin-chef pour la santé, Optum UK

MBChB, MRCGP(2013), BMedSci (hons), DFSRH, DRCOG, PGDipDerm (Distn)

Le Dr Krishna Vakharia est un médecin généraliste du NHS. Elle est également examinatrice régulière pour le diplôme de troisième cycle en dermatologie pratique à l'Université de Cardiff, ainsi que médecin-chef pour la santé chez Optum UK.

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