Halitosis is a frequent or persistent unpleasant breath odor.
Pathophysiology: It occurs due to fermentation of food particles by anaerobic gram-negative bacteria in the mouth, producing volatile sulfur compounds such as hydrogen sulfide and methyl mercaptan. 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 etc.
Causes: Bacteria on dorsum of tongue
Gingival or periodontal disease
Often history of poor oral hygiene
Necrotic oral cancer (rare—usually identified before becoming necrotic)
Extraoral disorders
Nasal foreign body*
Purulent or bloody nasal dischargeNecrotic nasopharyngeal cancer*
Necrotic pulmonary infection (eg, lung abscess, bronchiectasis, foreign body)
Productive cough
Psychogenic halitosis
Sinus infection*
Zenker diverticulum
Gastroesophageal reflux disease (GERD)
Alcoholic beverages, garlic, onions, tobacco.
Certain foods or spices, after digestion, release the odor of that substance to the lungs; the exhaled odor may be unpleasant to others. For example, the odor of garlic is noted on the breath by others 2 or 3 hours after consumption, long after it is gone from the mouth.
presence of orthodontic devices or dentures can cause halitosis if good dental hygiene is not maintained. Halitosis can also be caused by decaying food particles embedded in cryptic tonsils.