Mouth ulcers, also called canker sores, aphthous stomata and recurrent aphthous stomatitis, mostly occur on the inner cheek, inner lip, tongue, soft palate, floor of the mouth, and sometimes the throat. They are usually about 3-5mm in diameter - though for those sufferring chronic mouth ulcers often significantly larger, and appear 2 or 3 at a time, or worse still there can be 10-20 or more.

From this image one can deduce that, in sensitivity terms, a large mouth ulcer could be more significant than ones tackle - not a pretty thought.

They often seem start by themselves as a small bubble or blister (this stage is easy to not notice) which then becomes an open and ulcerated pit or crevass when the pain really starts. Alternatively they can be started by trauma to the lining of the mouth (e.g. by accidently biting onesself). The worst thing about mouth ulcers is the pain that they cause, which is constant, excruciating and made worse by eating, drinking and talking. The picture of the homunculus that you may recall from schooldays shows how very sensitive the mouth and tongue are compared to most other parts of the body - which explains the amount of discomfort caused by something so small. Severe ulcers cause sufferers to actively avoid eating, drinking, talking and kissing, which can be awkward socially. Speech is painful resulting in a loss of clarity or enunciation - and sometimes spitting, which doesn't help. Sufferers often get worn down by the pain and become fatigued and depressed, and so I have been told, irritable too. No specific single cause has yet been isolated, though it seems they are not generally caused by infectious agents such as viruses or bacteria and are therefore not considered contagious.

The current popular theory is that they are linked to the auto-immune system and an allergic reaction, in that certain triggers (that may be different from one person to the next) cause the mucosal lining (protective layer on the cheeks, gums, tongue, throat etc.) to become compromised, such that it is attacked by one's own saliva, or unfriendly bacteria within it.

To quote Stephen T. Sonis in his paper "The Pathobiology of Mucositis" (see the features section)... There are a substantial amount of data to indicate that mucositis results from a series of dynamic and interactive molecular and cellular events that involve all the elements of the mucosa (mucositis is the condition that causes the mouth ulcers to form).

This does go some way to explain why a definitive "cause" and "cure" is proving so elusive, but does not provide comfort for chronic sufferers of the cursed things. My own theory follows:

The making of a mouth ulcer

Ulcers start as a result of physical damage (1) which is easy to see, or by an allergic reaction or auto-immune system response to chemical or biological agents (2).

1) Physical damage. Accidentally biting ones cheek or tongue, puncture wounds caused by objects such as sharp crisps, wear and tear from vigorous licking!

2) For someone who has an allergic reaction or auto-immune system response to chemical or biological agents, these can initiate the formation of ulcers. The primary damage takes place underneath the surface causing cells to die within the connective tissue. Initially nothing looks or feels wrong until the damage reaches the surface and the ulcer suddenly ‘appears from nowhere’.

There is now a wound in the lining of the mouth caused by one of the events described above. In the mouth there are many good and bad micro-organisms and bacteria, which now have access to the wound surface. If too many bad bacteria get to colonise the wound, they take over, and produce toxins which in turn promote further cell death causing the ulcer to get larger (this is the stage it which it really hurts). Also at this stage the bacteria lining the ulcer surface can produce a fibrillous exudate which effectively makes a protective coating over their new home (this can often be seen as a whitish covering to the ulcer surface). This situation now continues until the causative agent is gone, and the body’s immune system comes up with the solution and the bad bacteria are quashed. How long this takes depends on many factors.

Prevention

In the case of physical damage (1) there is not much one can do to prevent it, except by obvious things such as; avoiding sharp foods, having sharp or chipped teeth smoothed off, or wearing a bite splint.

For ulcers caused by an allergic reaction or auto-immune system response to chemical or biological agents (2), prevention is difficult as it is very hard to isolate the agents responsible, especially as it can take a number of days between cause and visible effect.

Protection

There are a number of ways of adding protection to make the lining of the mouth as healthy as it can be, and thus be best able to resist physical damage and the actions of undesirable agents (obviously I am not going to say eat healthily, keep fit, get lots of rest and avoid stress, because life just isn’t like that all of the time, or any of the time sometimes):

Amino acids are the building blocks of life, L-Lysine has been highly beneficial in many cases. Supplements containing a whole range of fundamental amino acids are also now readily available.

Avoid (or at least don’t over-use) mouthwashes and toothpaste with a powerful anti-microbial action, they will get rid of the good guys as well as the bad, so if the balance is bad, it will still be bad.

Avoid toothpaste with harsh detergents such as sodium lauryl sulfate (SLS).

B vitamins are generally cited as being beneficial, particularly B12. B vitamins are not stored in the body so choose a supplement with a prolonged or slow release.

Products containing hyaluranon (hyaluronic acid) actively assist in tissue regeneration and can prevent ulceration caused by physical damage, and help protect connective tissue from damage caused by undesirable agents.

Tip the bacteria balance in your favour by adding more good guys, acidophilus, natural yoghurt, pro-biotic supplements have all been beneficial. Products containing xylitol also help by getting rid of some of the bad guys (e.g. strep mutans which helps cause plaque and bad breath).

When you have an ulcer, if that whitish coating appears, and you can stand the pain, slough it off.

If you have a mouth ulcer that is causing you worry, visit your doctor. 1 in 5 people get mouth ulcers, so the chances of it being anything life threatening are very remote. The tests for allergies and the big C are quick and easy - so if yer not sure, get it checked.