Cause |
Common Features* |
Tests |
Disorders in the mouth (oral) |
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Bacteria on the back of the tongue |
Unpleasant-smelling tongue scrapings Healthy gums and teeth |
A doctor’s or dentist's examination |
Periodontal disorders, such as gingivitis and periodontitis |
Affected gums and teeth noted during the examination In people with a history of poor oral hygiene |
A dentist’s examination |
Cancers of the mouth (most are identified during a doctor's or dentist's examination long before they cause bad odors) |
Usually identified during the examination More common among older people, who often have an extensive history of using alcohol and/or tobacco |
Biopsy, CT, or MRI |
Disorders outside the mouth (extraoral) |
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A foreign object (body) in the nose† |
Often a pus-filled or bloody discharge from the nose Seen during the examination Usually in children |
A doctor's examination Sometimes imaging |
Cancer of the nasal passages and upper throat† |
Discomfort when swallowing |
A doctor's examination |
Lung infections, such as a lung abscess, bronchiectasis, or an infection caused by an inhaled foreign object |
Cough that produces blood or sputum (phlegm) Fevers |
Chest x-ray Cultures of sputum Sometimes CT or bronchoscopy |
Imagined halitosis (psychogenic halitosis) |
Unpleasant smell not detected by others Often in people known to exaggerate other normal body sensations |
A doctor's examination Sometimes a consultation with a psychologist |
Sinus infection† |
A pus-filled discharge from the nose Face pain, headache, or both |
A doctor's examination Sometimes CT |
Gastroesophageal reflux disease |
Spitting up of undigested food (regurgitation) when lying down or bending over |
Video of the upper digestive tract after barium is given by mouth (barium swallow) |
Swallowed or inhaled substances |
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Alcoholic beverages, garlic, onions, tobacco |
Apparent based on the person's history Diagnosed after the doctor's examination rules out other causes |
A doctor's examination Avoidance of the substance to see if symptoms go away |
* Features include symptoms and the results of a doctor's or dentist's examination. Features mentioned are typical but not always present. |
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† The odor is typically more noticeable from the nose than from the mouth. |
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CT = computed tomography; MRI = magnetic resonance imaging. |