Aphthous ulcers

Aphthous ulcers, often called canker sores, are painful inflammatory lesions or spots on the inside of the mouth. Most often, people develop minor aphthous ulcers, which is where the lesions are a few millimeters across, round or oval in shape, and disappear within a week.

There are also two other unusual variations, however, major aphthous ulcers and herpetiform ulcers, which are much more severe and debilitating.

The underlying cause of this inflammatory disease is not well understood. One theory suggests tissue specific autoimmunity, where a localized cell-mediated immune reaction happens in the oral mucosa creating an accumulation of T-cells, specifically T helper cells Th1 cells, and macrophages, as well as chemokines like interferon-gamma and tumor necrosis factor.

Aphthous ulcers typically arise, either singly, or a few at a time, on the inside of the lips and cheeks or under the tongue.

Initially there is a small raised bump of inflammation in your mouth, and as it heals it turns into an ulcer covered by a fibrous membrane “cap” that looks yellowish-white or gray with well defined margins.

The ulcer is typically surrounded by a characteristic red halo due to inflammation in neighbouring blood vessels. Aphthous ulcers are usually mildly painful and annoying, with individual lesions measuring a few millimeters across and healing within 7 to 10 days without scarring.

And these usually recur 3-4 times per year. There are some variations on this general pattern.

Some individuals have recurrent aphthous ulcers which is where the recurrence is more frequent - sometimes each month, and this starts during childhood and resolves around age 40.

Another variation is major aphthous ulcers which describes lesions that measure over one centimeter in size and are generally more painful, last longer, and recur frequently.

Major aphthous ulcers can take between 10 days to over a month to heal, and can also leave a scar. Finally there are herpetiform ulcers, which typically affect women, and despite their name are not linked in any way to the herpes virus.

Herpetiform ulcers start out as clusters of tiny discrete ulcers that coalesce to form large, ulcerated patches in the mouth.

Although they heal in about 10 days, new crops of ulcers recur so frequently that they are effectively continuously causing pain and difficulty with eating and drinking.

Aphthous ulcers are non-contagious, non-sexually transmissible, and idiopathic, meaning that it's not clear why some people get aphthous ulcers and others don’t.

Many people with aphthous ulcers do have family members with the same problem, so there could be a genetic link. There are also well known external triggers, like a physical injury inside the mouth, like a bit lip, badly fitting dentures, or overzealous tooth-brushing which can all trigger the development of a lesion; as well as stress and anxiety, which seem to play a role in the pathogenesis of various inflammatory diseases.

Individuals with systemic immune system disorders like celiac disease and HIV infection are more prone to getting aphthous ulcers, and it’s also pretty common for people with nutritional deficiencies to have recurrent recurrent ulcers, which may be improved with diet and nutrient replacement.

It’s also common for people who stop smoking to develop aphthous ulcers, but it’s unclear if this is a direct effect of tobacco preventing ulcers or an indirect factors like increased stress and anxiety while quitting smoking.

A detailed history along with a typical appearance of an aphthous ulcer is all that’s needed to make a diagnosis. But aphthous ulcers can pop up as a symptom of another systemic immune system disorders like Crohn’s disease, so occasionally a more extensive workup is done.

There is no cure for aphthous ulcers, so the main goal is to identify and avoid triggers. Sometimes, topical analgesics and corticosteroids can be used to relieve pain and inflammation.

Alright, as a quick recap, aphthous ulcers are small painful sores inside the mouth that are most often triggered by trauma inside the mouth and take about a week to heal.

The underlying cause of aphthous ulcers is unknown, but it seems to be an autoimmune process in the oral tissue that involves Th1 cells, which can also sometimes be related to an underlying systemic disease.

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