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Probability diagnosis

  • Dietary habits

  • Poor oral hygiene

  • Oro-dental disease (esp. gingivitis, discharging abscess)

  • Dry mouth (e.g. on waking)

  • Smoking/alcohol

Serious disorders not to be missed


  • lung, oropharynx, larynx, stomach, nose, leukaemia

Pulmonary tuberculosis


Lung abscess

Blood dyscrasias/leukaemia


Hepatic failure

Pitfalls (often missed)

Nasal and sinus infection


Mouth breathing

Systemic infection



GORD/Hiatus hernia


  • pharyngeal and oesophageal diverticula

  • Sjögren syndrome

  • scurvy

Masquerades checklist


Diabetes (acetone)

Drugs (e.g. antidepressants, isosorbide)

Is the patient trying to tell me something?

Possible manifestation of psychogenic disorder (e.g. depression).

Key history

  • General health

  • Respiratory history

  • Gastrointestinal history including dry mouth and reflux

  • Dental history

  • Drug history including OTC preparations, alcohol and smoking

  • Dietary history: ask about onions, garlic, peppers, curries, spicy salami and similar meats, strong cheeses and water intake

  • Psychosocial history

Key examination

  • Orodental inspection, also oropharynx, nose and sinuses

  • Respiratory system

  • Abdominal examination

Key investigations

  • FBE


  • Urine analysis

  • Blood sugar

  • Kidney function tests

  • Liver function tests

  • X-ray of sinuses

  • Consider CT scan sinuses

Diagnostic tips

  • If cause is unknown refer to a dental surgeon; consider an ENT opinion.

  • Bacterial putrefaction of dental and food debris plus inflammation of the gums are largely responsible for oral malodour.

  • Smoking, alcohol and a dry mouth all aggravate the problem.

  • One survey indicated that 87% had an oral cause, 8% ENT and 5% an unidentified cause.

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