Aphthous ulcer

An aphthous ulcer (aka canker sore) is a type of oral ulcer which presents as a painful open sore inside the mouth or upper throat, caused by a break in the mucous membrane. The condition is also known as aphthous stomatitis, and alternatively as "Sutton's Disease," especially in the case of multiple or recurring ulcers.

The term aphtha means ulcer; it has been used for many years to describe areas of ulceration on mucous membranes. Aphthous stomatitis is a condition which is characterized by recurrent discrete areas of ulceration which are almost always painful. Recurrent aphthous stomatitis (RAS) can be distinguished from other diseases with similar-appearing oral lesions, such as certain viral exanthems or Herpes simplex, by their tendency to recur, and their multiplicity and chronicity. Recurrent aphthous stomatitis is one of the most common oral conditions. At least 10% of the population suffers from it. Women are more often affected than men. About 30–40% of patients with recurrent aphthae report a family history.^[1]

Presentation

Recurrence

Recurrent Aphthous Stomatitis is a T-cell mediated localized destruction of oral mucosa associated with an increased relative ratio of CD8+ T-cells to CD4+ T-cells.

Minor ulcerations

This is the most common and least severe form of the disease. Aphthous ulcers develop in childhood and adolescence, and continue sporadically throughout life. Aphthous ulcers occur exclusively on non-keratinized, movable mucosa, such as buccal (cheeks) and lingual mucosa, the floor of the mouth, and the soft palate. It is characterized as a yellow-gray ulcer surrounded by an erythematous halo less than 10 mm in diameter. They tend to heal without scarring in 7–10 days. Typical treatment is with topical steroids, although treatment is not necessary for healing to occur.

Major ulcerations

Major aphthous ulcers have the same appearance as minor ulcerations, but are greater than 10 mm in diameter and are extremely painful. They usually take more than a month to heal, and frequently leave a scar. These typically develop after puberty with frequent recurrences. They occur on moveable non-keratinizing oral surfaces, but the ulcer borders may extend onto keratinized surfaces. The lesions heal with scarring and cause severe pain and discomfort.

Herpetiform ulcerations

This is the most severe form. It occurs more frequently in females, and onset is often in adulthood. It is characterized by small, numerous, 1–3 mm lesions that form clusters. They typically heal in less than a month without scarring. Palliative treatment is almost always necessary.^[2]

Symptoms

Aphthous ulcers often begin with a tingling or burning sensation at the site of the future mouth ulcer. In a few days, they often progress to form a red spot or bump, followed by an open ulcer.

The aphthous ulcer appears as a white or yellow oval with an inflamed red border. Sometimes a white circle or halo around the lesion can be observed. The grey-, white-, or yellow-colored area within the red boundary is due to the formation of layers of fibrin, a protein involved in the clotting of blood. The ulcer, which itself is often extremely painful, especially when agitated, may be accompanied by a painful swelling of the lymph nodes below the jaw, which can be mistaken for toothache.

Causes

The exact cause of many aphthous ulcers is unknown. Factors that provoke them include stress, fatigue, illness, injury from accidental biting, hormonal changes, menstruation, sudden weight loss, food allergies, the foaming agent in toothpaste (SLS), and deficiencies in vitamin B12, iron, and folic acid.^[3] Some drugs, such as nicorandil, also have been linked with mouth ulcers. In some cases they are thought to be caused by an overreaction by the body's own immune system. The ones for which a cause is known are normally caused by viruses infecting the mouth, such as Herpes simplex.

Trauma to the mouth is the most common trigger of aphthous ulcers.[1][2][3] Physical trauma, such as that caused by toothbrush abrasions, laceration with sharp foods or objects, accidental biting (particularly common with sharp canine teeth), or dental braces can cause mouth ulcers by breaking the mucous membrane. Other factors, such as chemical irritants or thermal injury, may also lead to the development of ulcers. The large majority of toothpastes sold in the U.S. contain Sodium lauryl sulfate (SLS), which is known to cause aphthous ulcers in certain individuals. Using a toothpaste without SLS will reduce the frequency of aphthous ulcers in persons who experience aphthous ulcers caused by SLS.^[4]^[5]^[6] However, some studies find no connection between SLS in toothpaste and mouth ulcers.^[7]

A possible cause of aphthous ulcers in a susceptible population is gluten intolerance (Celiac disease), whereby consumption of wheat, rye, barley and sometimes oats, results in chronic mouth ulcers. However, two small studies of patients with Celiac disease did not demonstrate a link between the disease and aphthous ulcers. ^[8]^[9] On the other hand, one of the same studies concluded that one-third of its test group found relief from canker sores after eliminating gluten from the diet ^[8] This means observing a strict diet, eliminating breads, pastas, cakes, pies, scones, biscuits, beers and so on from the diet and substituting gluten-free varieties where available. The opportunity to go into such a drastic measure is to be balanced with its potential benefits.

Although the exact cause is not known, aphthous ulcers are thought to form when the body becomes aware of and attacks molecules which it does not recognize.^[10] The presence of the unrecognized molecules garners a reaction by the T-cells, which trigger a reaction that causes the damage of a mouth ulcer. People who get these ulcers have lower numbers of regulatory T-cells.^[10]

Repeat episodes of aphthous ulcers can be indicative of an immunodeficiency, signalling low levels of immunoglobulin in the mucous membrane of the mouth.^{citation needed} Certain types of chemotherapy cause mouth ulcers as a side effect.^[11] Mouth ulcers may also be symptoms or complications of several diseases listed in the following section. The treatment depends on the believed cause.

Treatment

Non-prescription treatments

In most cases treatment is not required and the ulcers will disappear on their own. Suggestions to reduce the pain caused by an ulcer include avoiding spicy food, rinsing with salt water or over-the-counter mouthwashes, proper oral hygiene and non-prescription local anesthetics.^[12] Active ingredients in the latter generally include benzocaine,^[13] benzydamine or choline salicylate.^[14] Anaesthetic mouthwashes containing benzydamine hydrochloride have not been shown to reduce the number of new ulcers or significantly reduce pain,^[15] and evidence supporting the use of other topical anaesthetics is very limited though some individuals may find them effective.^[16] In general their role is limited; their duration of effectiveness is generally short and does not provide pain control throughout the day; the medications may cause complications in children.^[17] Evidence is limited for the use of antimicrobial mouthwashes but suggests that they may reduce the painfulness and duration of ulcers and increase the number of days between ulcerations, without reducing the number of new ulcers.^[18] Liquorice root extract may help heal or reduce the growth of canker sores if applied early on and is available in over-the-counter patches.^[19] A mixture of equal parts water and hydrogen peroxide applied to the ulcer may speed healing, and applying Milk of Magnesia after this treatment can relieve discomfort.^[12]

Prescription treatments

Multiple ulcers may be treated with an antiviral medication. The application of silver nitrate will cauterize the sore; a single treatment reduces pain but does not affect healing time.^[22]

Prevention

Oral and dental measures

Nutritional therapy

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