Nose and throat causes of bad breath

Bad breath….we all have this sometimes, perhaps far more often than we know, and almost always when we do not want it like when we are about to meet an important client or on that important date, wanting to impress. Usually the causes of bad breath are due to foods, drinks and habits like garlic and onions, alcohol and smoking cigarettes, cigars or pipe tobacco. But bad breath can occur in health as much as in illness. Often we are able to tell if the bad breath is due to foods, drinks, smoking or illness.

So what causes bad breath in illness? Essentially our nose, mouth, throat and lower aero-digestive tracts (esophagus, lung, stomach, intestines) are colonized with bacteria at all times. The distribution of the different bacterial types ensures a nice equilibrium for health usually, and the continuous production of saliva and nasal mucus ensures that this population of bacteria remains well controlled. However when a nose and throat condition occurs to change this environment, especially to make it drier than the normal, the balance can change to favor bacterial overgrowth and/or the wrong bacterial type. In any and all situations for diseases causing bad breath, it is the change in the bacterial growth that causes the bad smells.

Let’s first look at the commonest causes of bad breath - a dry mouth. Whether the nose is blocked due to nose allergy or infection, the mouth tends to be drier as the mouth is now used to breath. This slowly changes the bacterial environment. This dry mouth feature is seen amongst us with obstructive sleep apnea and snoring where our noses tend to be blocked especially at night. Also some conditions may cause our salivary glands to shrink and produce less saliva e.g. Sjogren’s disease, radiation therapy, etc.

Mouth breathing has other consequences too. In addition to the bacterial change, a dry mouth predisposes us to gum disease and tonsil infections with consequently more infective bacterial colonization. If you have ever flossed your teeth, you will realize the fetor (bad smell) of the bacterial overgrowth that collects in the gum line. “Furring” of the tongue also occurs with mouth breathing. This means that the skin lining of the tongue becomes thicker and therefore can support more bacterial overgrowth. As for our tonsils, they have craters on the surface with sometimes deep skin-lined fissure that go deep into it. These fissures can collect bacteria with dead skin, be a source of bad breath and in some of us, produce “tonsils stones” which are the smelly soft and yellow-brown balls sometimes seen in the saliva we spit out.

Sinusitis is another cause of bad breath, with the smell coming from the nose. When the sinus openings are blocked, infection with pus can build up in the sinuses. This bad smell may sometimes be noted by the person himself and we call this “cachosmia”.  A more horrible Latin word is “ozaena” where the bad smell is noted by others, and not necessarily by the sufferer. Sufferers with “ozaena” include unfortunate patients with previous radiation therapy to the nose and sinuses, or any disease that can severely damage the natural mucus production of the nose. If it becomes so excessively dry, sometimes with crust formation, “saprophytic bacteria” (bacteria with a liking for dead tissue) dominates, and is the cause for the bad breath. In children, an interesting cause of ozaena is a foreign body e.g. bead, cotton bud, etc., placed in the nose, usually by the child. This becomes a source of infection and bad breath. Removal is necessary as well as to understand if the child is trying to tell us that they have a nose condition that requires treatment.

Thankfully the treatment philosophy is straightforward. Your doctor should investigate the cause and then treat the underlying problem either by medication, surgery or both. In addition, and at all times, good oral and nasal hygiene with good oral rehydration, tooth brushing, flossing, tongue scrapping, and saline nasal douching, should help to ensure  a sweeter breath for the day and night.

The Chinese version of this article was published in Hong Kong Economic Journal on  16 Jun, 2014