Halitosis

Halitosis is unpleasant breath noticed by the patient or others. About 85 to 90 percent of cases arise in the mouth, mainly from bacterial breakdown of proteins on the posterior tongue and in periodontal pockets, producing volatile sulphur compounds.

Mechanisms. Anaerobic bacteria degrade sulphur containing amino acids to hydrogen sulphide, methyl mercaptan and dimethyl sulphide. Reduced salivary flow, poor oral hygiene, tongue coating and periodontal disease raise production. Systemic causes excrete volatile compounds through the lungs.

Classification. Genuine halitosis (physiological, such as morning breath, and pathological, oral or extra-oral), pseudo-halitosis (no detectable odour, but the patient believes there is one) and halitophobia (persistent belief after treatment and reassurance).

Key distinctions. Odour present on mouth exhalation and absent on nose exhalation indicates an oral source. Odour on both indicates a systemic or airway source. Fruity (acetone) breath suggests ketosis, ammoniacal breath suggests uraemia, and fetor hepaticus suggests liver failure.

History. Onset, duration, constant or intermittent, relation to meals and mornings, oral hygiene habits, tongue cleaning, flossing, dental visits, dentures, dry mouth, bad taste, tonsil stones, postnasal drip, nasal obstruction or discharge, sinus symptoms.

Also ask about heartburn, regurgitation, dysphagia, cough and sputum, diet (garlic, onions, spices, fasting, low carbohydrate diets), tobacco, alcohol, khat and betel use, and medications. Ask about impact on social life, mood and obsessive thoughts.

Drug history. Drugs causing dry mouth (anticholinergics, antihistamines, tricyclic antidepressants, antipsychotics, diuretics, opioids), disulfiram, dimethyl sulphoxide, nitrates, chloral hydrate, metronidazole (taste), and cytotoxic drugs.

Examination. Organoleptic assessment by the clinician (smell mouth and nose exhalations separately, a spoon scraping of the posterior tongue, and flossed material), oral hygiene, plaque, gingivitis, periodontal pockets, caries, dentures, tongue coating.

Also oral ulcers, tonsils (crypts, stones), pharynx, nose (discharge, polyps, foreign body in children), neck nodes, salivary flow, abdomen, and signs of liver, kidney, diabetic and respiratory disease.

Red flags

• Unilateral foul nasal discharge in a child (foreign body)
• Ulcer, mass or white or red patch persisting over 3 weeks, or neck lump (oral or oropharyngeal cancer)
• Dysphagia, regurgitation of undigested food, or gurgling in the neck (Zenker diverticulum)
• Foul sputum, fever or haemoptysis (lung abscess, bronchiectasis)
• Ketones on breath with thirst and polyuria (diabetic ketoacidosis)
• Jaundice or confusion (liver failure)
• Weight loss, vomiting, or abdominal pain (gastric outlet obstruction, malignancy)
• Persistent belief of odour without objective findings, with depression or social withdrawal

Special groups. Children: nasal foreign body, tonsillitis, mouth breathing. Pregnancy: gingivitis and reflux. Older adults: dry mouth from drugs, dentures and dysphagia. Region specific: chewing of khat, betel nut and tobacco.

Oral (most common)

• Tongue coating and poor oral hygiene
• Gingivitis and periodontitis, necrotising ulcerative gingivitis
• Dental caries, dental abscess, pericoronitis, retained roots, failed restorations
• Dry mouth (xerostomia) from drugs, Sjogren syndrome, radiotherapy, dehydration, mouth breathing
• Dentures and orthodontic appliances
• Oral candidiasis, oral ulceration, oral cancer
• Tobacco, alcohol, betel nut and khat, and food (garlic, onion)

Ear, nose and throat

• Chronic tonsillitis and tonsilloliths
• Chronic rhinosinusitis, nasal foreign body, atrophic rhinitis, postnasal drip, nasal polyps
• Pharyngeal and laryngeal cancer
• Zenker diverticulum, oesophageal stricture, achalasia and oesophageal cancer

Respiratory and gastrointestinal

• Bronchiectasis, lung abscess, chronic bronchitis, cystic fibrosis, empyema
• Gastro-oesophageal reflux, Helicobacter pylori gastritis, gastric outlet obstruction
• Bowel obstruction (faeculent odour)

Systemic and metabolic

• Diabetic ketoacidosis and starvation ketosis (acetone)
• Uraemia (ammonia), liver failure (fetor hepaticus), trimethylaminuria (fishy odour), cystinuria, hypermethioninaemia
• Menstrual cycle, menopause, and dehydration

Non-organic

• Pseudo-halitosis and halitophobia (olfactory reference syndrome), obsessive compulsive disorder, depression, delusional disorder

Reasoning. Most patients need only oral and ENT examination. Test for systemic causes when the odour is on nose exhalation, unusual in character, or the oral examination is normal.

First line. Organoleptic test, dental and periodontal examination, tongue and tonsil inspection, and nasal examination.

Targeted tests.

• Halimeter or portable sulphide monitor, or gas chromatography, where available (volatile sulphur compounds over 100 to 150 parts per billion support genuine halitosis); a negative test with persistent complaint suggests pseudo-halitosis.
• Dental radiographs (panoramic or periapical) and periodontal probing.
• Nasal endoscopy and CT sinuses for chronic rhinosinusitis or foreign body.
• Flexible laryngoscopy and biopsy for suspicious oral or pharyngeal lesions. Barium swallow for suspected pharyngeal pouch or oesophageal disease, and upper gastrointestinal endoscopy for reflux, stricture or cancer.
• Capillary glucose and ketones, urea and creatinine, liver function and ammonia, thyroid function, full blood count, and urine for trimethylamine (after a choline rich meal) in suspected trimethylaminuria.
• Chest radiograph or CT for suspected lung abscess or bronchiectasis; sputum culture.
• Helicobacter pylori stool antigen or urea breath test when dyspepsia coexists.
• Screen for depression, anxiety and obsessive compulsive features when no source is found.

Limitations. Organoleptic assessment is subjective, and patients correlate poorly with measured odour. Meter readings are affected by diet, smoking and alcohol in the preceding hours.

Oral hygiene programme (all genuine cases). Brush teeth twice daily for 2 minutes, brush or scrape the posterior tongue daily (tongue scraper), floss or use interdental brushes daily, clean dentures out of the mouth at night in an antimicrobial solution, regular dental scale and polish, and stay hydrated. Avoid alcohol containing mouthwashes, which dry the mouth.

Mouthwash. Chlorhexidine 0.2 percent mouthwash, 10 mL rinsed for 1 minute twice daily for up to 2 weeks (staining of teeth and tongue, altered taste, and mucosal irritation; avoid long term use).

Cetylpyridinium chloride 0.05 to 0.07 percent mouthwash twice daily, or zinc containing rinses, for longer use.

Periodontal and dental disease. Dental treatment (scaling and root planing, treatment of caries and abscess, removal of retained roots). Necrotising ulcerative gingivitis: metronidazole 400 mg orally three times daily for 3 days with chlorhexidine rinses and dental debridement. Dental abscess: amoxicillin 500 mg orally three times daily for 5 days with drainage (metronidazole 400 mg three times daily for 5 days in penicillin allergy).

Dry mouth. Review and substitute culprit drugs, frequent sips of water, sugar free gum or lozenges, saliva substitutes, and fluoride care.

Pilocarpine 5 mg orally three times daily with meals (maximum 30 mg daily; avoid in asthma, angle closure glaucoma and cardiac conduction disease) for radiation or Sjogren related dryness.

Tonsilloliths and chronic tonsillitis. Gargles, oral irrigation, manual removal, and tonsillectomy for refractory symptoms.

Sinonasal disease. Saline irrigation, intranasal corticosteroid (mometasone 50 micrograms, 2 sprays to each nostril once daily, maximum 200 micrograms daily), and removal of foreign body.

Reflux. Omeprazole 20 to 40 mg orally once daily before breakfast for 8 weeks and lifestyle measures. Helicobacter pylori eradication: omeprazole 20 mg twice daily, clarithromycin 500 mg twice daily and amoxicillin 1 g twice daily for 14 days (metronidazole 400 mg twice daily in place of amoxicillin in penicillin allergy), with local resistance patterns considered.

Zenker diverticulum and oesophageal disease. Referral for surgical or endoscopic treatment.

Systemic causes. Treat the cause:

• diabetic ketoacidosis (0.9 percent sodium chloride 1 L over the first hour, fixed rate insulin 0.1 units/kg/hour once potassium is over 3.3 mmol/L, and potassium replacement)
• liver or renal failure (specialist care)
• lung abscess and bronchiectasis (amoxicillin with clavulanic acid 625 mg orally three times daily for 2 to 4 weeks, or clindamycin 300 to 450 mg orally four times daily; physiotherapy and drainage)

Trimethylaminuria. Dietary choline restriction (eggs, liver, legumes, fish), acidic soaps (pH 5.5 to 6.5), and metronidazole 400 mg orally twice daily for 10 days each month in short courses by specialists; genetic counselling.

Pseudo-halitosis and halitophobia. Explanation with objective results, oral hygiene education, and cognitive behavioural therapy; selective serotonin reuptake inhibitor (sertraline 50 mg orally daily, increased to 100 to 200 mg daily if needed, with monitoring of sodium and suicidal thoughts) by psychiatry for halitophobia with obsessive features.

Monitoring. Review in 2 to 4 weeks after oral hygiene and dental treatment. If symptoms persist, test for extra-oral causes.

Referral and escalation. Dentist for all patients. ENT within 2 weeks for unilateral foul nasal discharge, persistent oral or throat lesions, or neck mass. Gastroenterology for dysphagia, reflux unresponsive to treatment or suspected pouch. Psychiatry for halitophobia.

Admission criteria. Diabetic ketoacidosis, liver failure, lung abscess with sepsis, or airway compromise from deep neck infection.

Discharge and safety netting. Return for oral ulcer over 3 weeks, swallowing difficulty, weight loss, vomiting, jaundice, thirst with polyuria, or unilateral foul nasal discharge.