Differential Diagnosis for Bad Halitosis

• Single most likely diagnosis
  • Poor oral hygiene: This is the most common cause of bad halitosis, as the bacteria in the mouth break down food particles and release volatile sulfur compounds, leading to bad breath.
• Other Likely diagnoses
  • Gingivitis or periodontal disease: Inflammation of the gums can cause bad breath due to the accumulation of bacteria and the release of volatile sulfur compounds.
  • Dry mouth (xerostomia): A lack of saliva can lead to an overgrowth of bacteria in the mouth, causing bad breath.
  • Tonsillitis or tonsil stones: Infection or inflammation of the tonsils can cause bad breath, especially if there are stones or debris trapped in the tonsillar crypts.
  • Gastroesophageal reflux disease (GERD): Stomach acid flowing up into the mouth can cause bad breath, especially after eating or at night.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Diabetes: Uncontrolled diabetes can lead to ketoacidosis, which can cause bad breath due to the production of acetone.
  • Kidney disease: Kidney failure can cause a buildup of waste products in the body, leading to bad breath.
  • Liver disease: Liver failure can cause a buildup of toxins in the body, leading to bad breath.
  • Lung cancer or other respiratory infections: In rare cases, bad breath can be a symptom of lung cancer or other serious respiratory infections.
• Rare diagnoses
  • Trimethylaminuria: A rare genetic disorder that causes the body to produce trimethylamine, a chemical that smells like fish or rotten eggs.
  • Sjögren's syndrome: An autoimmune disorder that can cause dry mouth and bad breath.
  • Nasal or sinus infections: In rare cases, bad breath can be caused by infections in the nasal passages or sinuses.
  • Medication side effects: Certain medications, such as chemotherapy or antidepressants, can cause bad breath as a side effect.