Bad Breath - Causes of Halitosis

Bad Breath
Bad Breath. fiverlocker/

Social interactions are an important part of our day-to-day activities. These social interactions can be affected when you have bad breath, or halitosis. This can be difficult for several reasons. You may not even know you have bad breath because of gradual tolerance to your own breath smell. You may also experience problems with your sense of smell with some causes of bad breath. Making this problem even more difficult or distressing for you is that your family and friends may not be comfortable telling you that you have a problem.

Oral Causes of Bad Breath

You currently have about 500 different types of bacteria in your mouth. It is easy for these bacteria to multiply as, the oral cavity is an ideal location for bacterial growth due to the average temperature of 37°C and humidity of 96%. The most common places for bacteria to grow are on coated tongues and in the space between your gum and your teeth, known as the periodontal space. About 90% of all cases of bad breath are related to food debris and plaque that causes:

  • caries (cavities)
  • gingivitis
  • periodontitis

Medications (like phenytoin, cyclosporin, and calcium channel blockers) can cause your gums to enlarge and increase your risk for bad breath. The relationship of periodontal disease and bad breath is not well understood, but the two are strongly associated.

Saliva helps to keep the level of bacteria in the oral cavity within normal limits. This is your body's natural way of cleaning your mouth.

Disorders can affect your production of saliva, leading to a dry mouth (xerostomia) including:

  • diabetes
  • Sjogren's syndrome
  • medications - antidepressants, antihypertensives (blood pressure), diuretics (water pills), and antipsychotics
  • radiation therapy
  • chemotherapy 

Other conditions that cause disease in your teeth can additionally cause symptoms of bad breath.

Improving your oral hygiene by flossing, brushing, use of mouth wash as prescribed by your dentist can decrease your risk of having bad breath when it is related to oral causes.

Non-Oral Causes of Bad Breath

Outside of the oral cavity, almost any body system (gastrointestinal, endocrine, blood, kidney, liver, etc...) have specific disorders which make up 8% of the cases of bad breath. These causes can not be identified as easily, because the oral cavity itself does not have a malodorous smell. Disorders related to the ear, nose and throat are some of the more common sources of bad breath outside of disorders of the mouth. 

Respiratory causes of halitosis include: bronchitis, bronchiectasis, and lung infections. Stomach disorders that cause bad breath include: hiatal hernia, Zenker's diverticulum, and pyloric stenosis. Liver, kidney, and blood disorders can also cause symptoms of bad breath. 

ENT-Related Causes of Bad Breath

Treatment of ENT-Related Bad Breath

Increasing oral hygiene in ENT-related bad breath will not resolve the problem. It may temporarily help mask the odor. However, unless the underlying cause is treated, the bad breath will not resolve. Each disorder will have it's own unique treatment that once used will resolve any symptoms of bad breath.


Aylıkcı, B.U. & Çolak, H. (2013). Halitosis: From diagnosis to management. J Nat Sci Biol Med. 4(1):14–23. doi: 10.4103/0976-9668.107255

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