Nov 142011

On this post we will focus on what is commonly known as sinus bad breath, or nasal bad breath, which are terms to describe oral malodours which mainly emanate from the nasal passages (although usually the odours can be perceived via the mouth as well, albeit no so intensely). As we will see, this type of halitosis is often caused by chronic sinus problems, sinus infections, sinusitis, rhinitis (runny nose) and/or post-nasal drip. 

Introduction – The Upper Respiratory Tract, Excess Mucus Production and Bad Breath:
Sinus Bad Breath (Nasal Bad Breath) - Upper Respiratory Tract
Sinus bad breath (or nasal bad breath) is mainly caused by conditions / diseases affecting the upper respiratory tract. It is worth mentioning that bad breath originating from conditions or diseases affecting the upper respiratory tract accounts for only around 10% of halitosis cases (dental problems – including periodontal disease, infected wisdom teeth, etc – as well as dry mouth, poor oral hygiene and coated tongue account for around 90% of cases of chronic bad breath).
These are the components of the upper respiratory tract:
  • Nose, nasal cavity and sinuses
  • Pharynx
  • Larynx
The area is also called upper airway and it usually refers to the parts of the respiratory system which are located outside of the thorax.
A normal person will produce a certain amount of mucous each day – it is estimated that between one and one and a half litres per day! I know you are probably not very keen on things mucous-related, but it turns out the substance does indeed serve a purpose!  We are actually covered in mucous-producing tissue: it can be found in the mouth, nose, sinuses, throat, lungs, gastrointestinal tract…
Mucous acts as a protective layer which prevents all tissues underneath it from drying out. In addition, mucous traps bacteria and harmful particles, preventing them from entering the body directly. It contains enzymes, antibodies and protein. Therefore, mucous protects, moistens and cleans the respiratory tract – a very important function indeed!
However, the negative side of the story is that the large amounts of protein contained in mucous are loved by anaerobic bacteria, which break down the proteins into foul smelling sulphur compounds. Hence sinus or nasal bad breath can occur if too much mucous is produced; and usually this mucous tends to accumulate in certain areas of the sinuses, nose, mouth or throat.
Both the consistency, composition and the quantity of mucous produced by the body can change from person to person, but there are situations where certain factors or conditions can trigger an overproduction of mucous and / or change its composition and thickness.
Most common colds have this effect, as we all know – but this is a temporary illness that usually goes away in a few days, so bad breath from a cold is temporary too.
Eating dairy – does not have to be in large amounts necessarily – will have the effect of increasing mucous production in most people, so if you have a problem with excess mucous it may be wise to watch the amount of dairy products you eat.
Here are the most common factors or conditions that can lead to an overproduction of mucous and hence sinus or nasal bad breath (we will refer mostly to chronic conditions from now on, since these are the ones directly related to chronic halitosis cases):
Chronic Sinusitis – Causes and Symptoms:
The sinuses are air-filled chambers located behind the forehead, cheeks, nasal bones and eyes, lined with mucous membranes which empty into the nasal cavity.
Chronically inflamed sinuses tend to produce large amounts of mucous. In addition, the sinuses can become blocked in this environment and large amounts of bacteria or other micro organisms such as fungi can reproduce very easily. Therefore, the mucous present when there is a sinus infection is infected itself, and this can create a pungent smell even before it is metabolised by the bacteria in the mouth.
Main causes of sinusitis:
  • Malfunctioning of the nasal cilia (tiny hairs that line the surface of the nasal cavity, helping to keep the nose clean, by moving mucous out, amongst other functions).
  • Common colds, or any other upper respiratory tract infections originally caused by viruses or bacteria, as well as certain allergies, can cause an overproduction of mucous which can eventually lead to a chronic blockage and / or inflammation of the sinuses.
  • Nasal polyps or a deviated nasal septum, which can also block the sinuses.
  • A fungal infection (see Step 10 for fungal sinusitis).
  • Infected upper teeth, molars or wisdom teeth, can sometimes affect the cheekbone and the maxillary sinuses (the roots of the upper teeth and molars are actually very close to the maxillary sinuses).
  • Swelling caused by allergies can lead to chronic inflammation and to excess production of mucous which can in turn lead to sinusitis.
  • Hormone imbalances or hormone changes can lead to excessive mucous productions. In particular, chronic sinusitis problems can sometimes be caused by the contraceptive pill.
Sinusitis can become chronic if it lasts more than about three months. Bacterial biofilms may be formed inside the nasal passages and sinuses, and this makes bacteria a lot stronger and difficult to get rid of.
Symptoms of Sinusitis
Symptoms of sinusitis:
  • Sinus or nasal bad breath and / or loss of smell
  • Persistent cough
  • Pressure and pain on different areas of the face (forehead, behind the eyes, cheeks, upper molars and teeth…)
  • Persistent headaches
  • Fever (not necessarily high)
  • Sore throat
  • Nasal Congestion and / or rhinitis (see next paragraph)
  • Nasal discharge: green, yellow or brown mucus, even orange-coppery colour
  • Post-nasal drip (see next section)
Chronic Rhinitis – Causes and Symptoms:
Rhinitis is an inflammation of the inner lining of the nose and can be caused by many other conditions or factors (such as colds, bacterial infections, allergies, sinusitis…), and it typically causes large amounts of mucous to be produced.
Symptoms of rhinitis:
  • Nasal itching and congestion
  • Runny nose
  • Sneezing
  • Watery eyes
Rhinitis can be classified as allergic rhinitis (such as the seasonal hay fever), non-allergic rhinitis (such as gustatory rhinitis – when you eat a spicy food for instance – or a runny nose trigged by temperature changes), and infective rhinitis (includes acute and chronic bacterial and viral infections).
While excess mucous may come out of the nose (runny nose), it can also drip down to the back of the throat via the back of the nose. This is Post-Nasal Drip – see below.
Post-Nasal Drip – Causes and Symptoms:
Post-Nasal Drip (PND) is caused by excessive mucous production, which tends to accumulate at the back of the nose, dripping downwards to the throat, accumulating there, in on around the tonsils and also coating the back of the tongue.
Note that post-nasal drip is often caused by rhinitis or sinusitis.
Post-nasal drip causes that frog-in-the-throat feeling, usually creating a need to constantly swallow and / or cough or clear the throat; this is because the thick mucous tends to cling at the back of the throat.
Post-Nasal Drip is the most common cause of chronic cough, particularly at night when lying down or first time in the morning when waking up. In addition, post nasal drip is very likely to have an active role in the production of tonsil stones inside the tonsils.
Summary – Sinus or Nasal Bad Breath Caused by Chronic Sinus Problems, Rhinitis or Post-Nasal Drip:
Sinus or nasal bad breath is often caused by conditions or infections affecting the upper respiratory system, in particular the sinuses and the nose. Excess mucous production and infection – caused by chronic sinus problems, rhinitis or post-nasal drip –  causes large amounts of bacteria to be present, who metabolise the proteins present in the mucous itself, causing the release of malodorous gases. This mucous can also drip down the back of the throat and end up inside the tonsil crypts or the surface of the tongue. Chronic bad breath is often caused by multiple conditions, infections or diseases so it is important to analyse all possible underlying factors so that the most effective treatment can be used.
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