Symptoms
A person may not always know that he or she has bad breath. This phenomenon is because odor-detecting cells in the nose eventually become accustomed to the constant flow of bad smells from the mouth. Others may notice and react by recoiling as you speak.
Other associated symptoms depend on the underlying cause of bad breath:
Poor dental hygiene — Teeth are coated with film or plaque, food debris trapped between teeth, pale or swollen gums
Infections in the mouth — Gums may be red, swollen and bleed easily, especially after brushing or flossing; pus may drain from between teeth; a pocket of pus (abscess) at the base of a tooth; loose teeth or a change in "fit" of a denture; painful, open sores on the tongue or gums
Respiratory tract infections — Sore throat, swollen lymph nodes ("swollen glands") in the neck, fever, stuffy nose, a greenish or yellowish nasal discharge, a mucus-producing cough
External agents — Cigarette stains on fingers and teeth, a uniform yellow "coffee stain" on teeth
Dry mouth — Difficulty swallowing dry foods, difficulty speaking for a prolonged period because of mouth dryness, a burning sensation in the mouth, an unusually high number of dental caries, dry eyes (in Sjögren's syndrome)
Systemic (bodywide) illnesses — Symptoms of diabetes, lung disease, kidney failure or liver disease