Diagnosis of halitosis

Halitosis is an unpleasant noxious odour emanating from the oral cavity.

Halitosis can have a self-limiting, intraoral or extraoral cause (see Common causes of halitosis). Definitive diagnosis can be difficult and requires a thorough dental and medical history. Examination of the nose, tonsils, mucosal surfaces of the pharynx and oral cavity, and teeth is required.

Self-limiting causes of halitosis are common on waking, usually due to low salivary flow and lack of oral cleansing during sleep. Oral malodour is the result of microbial degradation of various substrates into volatile compounds (eg sulfur). The dorsal surface of the tongue is the most likely location of the microbial population causing halitosis. Self-limiting causes of halitosis can be rectified by eating, rinsing the mouth with water and oral hygiene. Other causes of self-limiting halitosis include food (eg garlic, onion, spices), smoking and alcoholic beverages.

Intraoral causes of halitosis include poor oral hygiene or underlying pathology, most commonly intraoral infections (eg periodontal infections, pericoronitis). Although halitosis is the result of a complex interaction between several bacterial species, the most active bacteria are Gram-negative anaerobes that are associated with periodontal disease.

Extraoral causes of halitosis include systemic conditions, such as respiratory infections, gastrointestinal disorders, advanced kidney disease and ketoacidosis.

Perceived halitosis (without detectable oral malodour) may reflect a psychological illness. Other people’s behaviour, or perceived behaviour, such as covering the nose or averting the face, is typically misinterpreted by these patients as an indication that their breath is offensive.

Devices that objectively measure volatile sulfur compounds give variable results, are costly and are not recommended.

Poor oral hygiene or a poorly designed denture or bridge can result in accumulation of dental plaque and food debris, which can worsen halitosis.