Bad breath is a common complaint that nearly everyone will suffer from at some point in their life. Usually the problem can be kept under control by exercising good oral hygiene. Regular and thorough brushing and flossing and the use of mouthwash should be part of your day-to-day regime. 

However, a persistent problem with bad breath that does not respond to improvements in your oral hygiene could be a sign of a more serious underlying medical condition. Here are a few medical conditions associated with long-term halitosis: 

Cancers

It seems like a dramatic step to link halitosis with cancer. However, it can be an early warning sign and, if your persistent bad breath is coupled with one or more alarming symptoms, it is a good idea to make an appointment with your doctor as soon as possible. 

• Lung cancer. This is a particular risk if you are a smoker. A further problem with smoking is that the smell of cigarettes on your breath can mask the genuine odour. Other signs of lung cancer include a persistent cough, dramatic weight loss and difficulty breathing. 

• Mouth cancer. Again, this is a higher risk if you are a smoker. Signs include persistent mouth ulcers that do not heal, discolouration on the tongue or mouth lining and enlarged lymph nodes. 

• Stomach cancer. If you suffer from stomach ulcers alongside bad breath, there is a possibility that you could develop stomach cancer (this is cancer of the lining of your stomach).

Diabetes 

Both type I and type II diabetes can cause halitosis. Both strains of the disease are easy to diagnose as the particular breath scent caused by diabetes is very distinctive. It has been described by some as smelling like nail varnish remover. The scent is caused as, in diabetics, the body expels ketones (a byproduct of fat consumption) through the saliva glands. 

Kidney problems 

Again, the breath odour caused by kidney disease is distinctive and often very unpleasant. It is the result of high levels of ammonia in the body. Ammonia is processed by the kidneys and expelled in urine.  If there is a problem with kidney functioning, levels will build up and enter the blood stream.

This list is not exhaustive and there are many other causes of bad breath. However, if you suffer from chronic bad breath and are worried about the possibility of any of these conditions, make an appointment with your dentist and doctor.