Halitosis is a frequent or persistent unpleasant breath odor.
(See also Evaluation of the Dental Patient.)
Pathophysiology of Halitosis
Halitosis most often results from degradation of food particles by anaerobic gram-negative bacteria in the mouth, producing volatile sulfur compounds such as hydrogen sulfide and methyl mercaptan. Causative bacteria may be present in areas of periodontal disease, particularly when ulceration or necrosis is present. The causative organisms reside deep in periodontal pockets around teeth. In patients with healthy periodontal tissue, these bacteria may proliferate on the dorsal posterior tongue.
Factors contributing to the overgrowth of causative bacteria include decreased salivary flow (eg, due to parotid disease, Sjögren syndrome, or use of anticholinergic medications), salivary stagnation, and increased salivary pH.
Etiology of Halitosis
Most cases result from oral conditions (1). A variety of systemic and extraoral conditions account for the remainder (see table Some Causes of Halitosis).
The most common causes overall are the following:
Smoking
Ingested foods that have a volatile component
Gastrointestinal disorders rarely cause halitosis, because the esophagus is normally collapsed. However, certain disorders (eg, gastroesophageal reflux disease [GERD], esophageal diverticula, stomach cancer) may cause halitosis. It is a fallacy that breath odor reflects a state of digestion and bowel function.
Other breath odors
Several systemic diseases produce volatile substances detectable on the breath, although not the particularly foul, pungent odors typically considered halitosis. Diabetic ketoacidosis (DKA) produces a sweet or fruity odor of acetone, liver failure produces a unique mousy odor (musty, sweet, and/or sulfurous), and renal failure produces an odor of urine or ammonia.
Etiology reference
1. Fedorowicz Z, Aljufairi H, Nasser M, et al: Mouthrinses for the treatment of halitosis. Cochrane Database Syst Rev (4):CD006701, 2008. doi: 10.1002/14651858.CD006701.pub2. Update in: Cochrane Database Syst Rev (5):CD006701, 2016
Evaluation of Halitosis
History
History of present illness should ascertain duration and severity of halitosis (including whether other people have noticed or complained), adequacy of the patient’s oral hygiene, and the relationship of halitosis to ingestion of causative foods (see table Some Causes of Halitosis).
Review of systems should seek symptoms of causative disorders, including nasal discharge and face or head pain (sinusitis, nasal foreign body), productive cough and fevers (pulmonary infection), and regurgitation of undigested food when lying down or bending over (Zenker diverticulum). Predisposing factors such as dry mouth, dry eyes, or both (Sjögren syndrome) should be noted.
Past medical history should ask about duration and amount of use of alcohol and tobacco. Medication history should specifically ask about use of medications that can cause dry mouth (eg, those with anticholinergic effects—see table Some Causes of Xerostomia).
Physical examination
Vital signs are reviewed, particularly for presence of fever.
The nose is examined for discharge and foreign body.
The mouth is examined for signs of periodontal disease, dental infection, and cancer. Signs of apparent dryness are noted (eg, whether the mucosa is dry, sticky, or moist, and whether saliva is foamy, stringy, or normal in appearance).
The pharynx is examined for signs of infection and cancer.
Sniff test
If site of origin is unclear, the posterior tongue is scraped with a plastic spoon. After 5 seconds, the spoon is sniffed 5 cm from the examiner’s nose; a bad odor suggests the malodor is caused by bacteria on the tongue.
Red flags
The following findings are of particular concern:
Fever
Purulent nasal discharge or sputum
Visible or palpable oral lesions
Interpretation of findings
Because oral causes are by far the most common, any visible oral disease may be presumed to be the cause of halitosis in patients with no extraoral symptoms or signs, and a dentist should be consulted. When other disorders may be involved, clinical findings often suggest a diagnosis (see table Some Causes of Halitosis).
In patients whose symptoms seem to be related to intake of certain food or drink and who have no other findings, a trial of avoidance (followed by a sniff test) may clarify the diagnosis.
Testing
Extensive diagnostic evaluation should not be undertaken unless the history and physical examination suggest an underlying disease (see table Some Causes of Halitosis). Portable sulfur monitors, gas chromatography, and chemical tests of tongue scrapings are available but best left to research protocols or to specific dental offices that focus on halitosis evaluation and treatment.
Treatment of Halitosis
Regular oral hygiene and dental care
Cause treated
Underlying diseases are treated.
If the cause is oral, the patient should see a dentist for professional cleaning and treatment of gingival disease and caries
If the patient has a history of alcohol use disorder, nonalcoholic mouthwashes should be used. Psychogenic halitosis may require psychiatric consultation.
Geriatrics Essentials: Halitosis
Older patients are more likely to take medications that cause dry mouth, which leads to difficulties with oral hygiene (as do limited manual dexterity and conditions such as rheumatoid arthritis and Parkinson disease) and hence to halitosis, but they are otherwise not more likely to have halitosis. Also, oral cancers are more common with aging and are more of a concern among older than younger patients.
Key Points
Most halitosis results from degradation of food particles by anaerobic gram-negative bacteria that reside around the teeth and on the dorsum of the tongue.
Extraoral disorders may cause halitosis and are often accompanied by suggestive findings.
Home treatment includes enhanced toothbrushing, flossing, and tongue brushing or scraping.
Mouthwashes provide only brief benefit.
