Halitosis: what it is, types of bad breath and which bacteria cause it

Bad breath is a common problem that brings people to the dentist. The medical term "halitosis" (Latin halitus — breath) denotes not a separate disease but a sign that can have many causes. Let us break down how it works and what is known about it.

What halitosis is

Halitosis is the medical designation for stale breath; in dentistry the terms "ozostomia" and "foetor ex ore" are also found. The term itself appeared in 1920 as an advertising ploy to promote a mouthwash, but it took hold as a neutral description of a symptom. Halitosis refers to an odor whose source is the microflora of the oral cavity and the products of its vital activity, rather than any single disease.

Types of bad breath and how they differ

The character of the odor is linked to which volatile compounds predominate. Anaerobic bacteria feeding on dense protein plaque on the tongue, teeth and inner surface of the cheeks release sulfur compounds: hydrogen sulfide gives the smell of rotten eggs, methyl mercaptan — of feces and rotten cabbage, dimethyl sulfide — a sweetish "cabbage-sulfur" note. Non-sulfur compounds include cadaverine (cadaverous odor), putrescine (rotting meat), skatole and indole (feces, naphthalene), trimethylamine and dimethylamine (fishy, ammoniacal note), ammonia and isovaleric acid with the smell of sweat and spoiled cheese. A specific odor is also described separately in certain diseases and medications — for example, the smell of acetone in diabetic coma.

Which bacteria cause bad breath

Normally the oral cavity is dominated by aerobic microflora, which keeps anaerobic microflora in check. Halitosis develops when there is an imbalance: the number of anaerobic microorganisms grows — Escherichia coli, Solobacterium moorei, certain streptococci and a number of gram-negative bacteria. It is the products of their protein breakdown that create the odor. The same mechanism explains why the odor intensifies with poor hygiene, caries, gum disease and poorly made dentures.

Other causes of halitosis: mouth, nasopharynx, internal organs

The causes go beyond the oral cavity. Among them are diseases of the upper respiratory tract and pharynx (chronic rhinitis, pharyngitis, tonsillitis, nasal polyps), chronic nonspecific lung diseases, pathologies of the stomach and glands, impaired digestion, renal failure, oncological diseases, stress, fasting and the intake of medications that cause dry mouth. In children, gastroesophageal refluxes are most often cited; the widespread belief about a link with worms is a prejudice.

How doctors assess bad breath and look for the cause

It is difficult to assess one's own breath: the literature describes methods of self-checking (the smell of plaque from the tongue, the smell of dried saliva), but they only indirectly indicate the presence of halitosis. If chronic tonsillitis is suspected, the help of an otolaryngologist is needed. If the odor does not go away after several weeks of ordinary hygiene, it makes sense to discuss this with a dentist.

When bad breath requires seeing a doctor

• the odor persists after several weeks of ordinary oral care;
• the gums hurt, bleed or are swollen;
• there is toothache or teeth are loose in an adult;
• problems with dentures.

Bad breath by itself is not a reason to call an ambulance; 103/112 — if an acetone odor occurs against the background of diabetic coma (loss of consciousness) or signs of a life-threatening condition appear, for example symptoms of a stroke or heart attack.

This material is for reference: it explains the mechanisms but does not replace a doctor's consultation — the decision on testing and management remains with you and your dentist.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer