Halitosis

Synonym: Bad breath

George Orwell wrote that "You can have affection for a murderer, but you cannot have an affection for a man whose breath stinks." [The Road to Wigan Pier, published 1937]

Halitosis is an unpleasant odour emitted from the mouth.

Halitosis may be due to:

• Artificially induced halitosis e.g. after eating a particularly aromatic meal
• Underlying systemic disease
• Pseudo-halitosis i.e. people who falsely believe they have bad breath

Breath smells when certain aromatic chemicals are found within it; these include hydrogen sulphide, methyl mercaptan and dimethyl sulphide.
Sources of bad breath include:

• The commonest causes of occasional halitosis include:
  • Smoking cigarettes or cigars
  • Drinking alcohol
  • Eating certain foods e.g. garlic, onions, highly spiced food
• Another cause is crash dieting, or protein only diets:
  • After a few hours the body begins to break down its fat stores and ketones are released.
  • These give the breath a distinctive sweet and sickly smell.
• Originating from the mouth:
  • Altered blood around the gum can be an important cause and may be found with debris or pus due to gingivitis and periodontal pockets.¹
  • Acute ulcerative gingivitis is associated with a typical form of halitosis.
  • Acute necrotising ulcerative gingivitis (Vincent's disease, trench mouth) causes the most notable halitosis.
  • Dry mouth is a common cause along with smoking.
  • Patients may confuse bad breath with bad taste in the mouth.
  • Plaque on the teeth is not a major cause of halitosis but patients should be advised to exercise careful tooth care.
  • Bacteria colonizing the tongue and periodontal pockets play an important role in the production of volatile sulphur compounds which can cause halitosis. Regular brushing of the tongue is helpful.²
  • Fixed dentures intensify the development of halitosis, as they make difficult or even completely impede the complex of oral cavity hygiene measures.³
• Originating from the nasopharynx:
  • Chronic sinusitis and post nasal drip are common causes.
  • Foreign bodies in the nose can produce a striking odour to the breath.⁴
  • Occasionally chronic tonsillitis and atrophic rhinitis can be causes.
• Respiratory tract infections cause bad breath infrequently.
• GI disorders:
  • Acid reflux:
    • Commonly believed to be a cause although little evidence.
    • One hundred and sixty general practitioners were selected and a postal survey was conducted.⁵
    • A 94% response rate showed that the commonest symptoms for which proton pump inhibitors are prescribed are heartburn (65%).
    • Halitosis and/or bitter taste was the stated complaint in 1%.
  • H. pylori has been found in up to 87% of patients with halitosis, acid taste and burning sensations in the mouth.⁶
• Systemic disorders:
  • Diabetes, renal or liver disease.
  • Bronchiectasis and other lung infections, such as in cancer, may also cause halitosis.
  • Often all these can be excluded and still no cause found.
  • It may be related to patient being fixated about bad breath as an expression of his/her emotional or sexual problems.
• Fish odour syndrome (trimethylaminuria):⁷
  • This is is a rare disorder characterised by longstanding oral and body malodour.
  • It is caused by an excess of trimethylamine due to a metabolic oxidation defect that produces a pungent ammoniacal odour similar to that of rotten fish.
• Hypermethioninaemia is another rare metabolic disorder that can lead to oral malodour.⁸

Drugs

The following may also cause halitosis:⁴

• Alcohol
• Tobacco
• Betel
• Solvent misuse
• Chloral hydrate
• Nitrites and nitrates
• Dimethyl sulphoxide
• Disulphiram
• Some cytotoxic agents
• Phenothiazines
• Amphetamines

There are no reliable estimates of prevalence, although several studies report the population prevalence of halitosis (physiological or because of underlying disease) to be about 50%.⁹

• During sleep the flow of saliva is drastically reduced and the tongue and cheeks move very little.
• This allows food residues to stagnate in the mouth and dead cells that are normally shed from the surface of the tongue and gums and from the inside of the cheeks to accumulate.
• As bacteria start to work on them and digest them, an unpleasant smell is generated.
• Although normal, anyone suffering from nasal congestion who mouth-breathes is more likely to suffer from these actions to a greater extent.

The clinical assessment of halitosis is usually subjective and is based on smelling air from the mouth and nose and comparing the two - organoleptic assessment.

• Odour detectable from the mouth, but not from the nose is likely to be of oral or pharyngeal origin.
• Odour from the nose alone is likely to be coming from the nose or sinuses.¹⁰
• In rare instances when the odour from the nose and mouth are of similar intensity, a systemic cause of the malodour may be likely.

There is no consensus regarding duration of bad breath for diagnosis of halitosis, although the standard organoleptic test for bad breath involves smelling the breath on at least two or three different days.⁹

• Investigate and manage possible systemic (non-oral) source if organoleptic method detects malodour from both mouth and nose
• Improve oral hygiene by professional and patient administered tooth cleaning¹
• Regular atraumatic tongue cleaning¹¹
• Regular use of antimicrobial toothpastes and mouthwashes, such as:
  • Chlorhexidine gluconate¹²
  • Oil-water rinse¹³
  • Triclosan/co-polymer/sodium fluoride toothpaste¹⁴
• Two RCTs have found that regular use of a mouthwash reduces breath odour at 2 to 4 weeks compared with placebo.^15,16 People in the active treatment group had significantly more tongue discolouration than people using placebo mouthwash after 2 weeks.
• Regular clinical review to ensure maintenance of effective oral hygiene
• Halitophobia (fixated with teeth cleaning and tongue cleaning and frequently use chewing gums, mints, mouthwashes, and sprays in the hope of reducing their distress¹⁷) warrants referral to clinical psychologist.
• Eradication of H. pylori in patients with functional dyspepsia and halitosis results in sustained resolution of halitosis during long-term follow-up in the majority of cases.