Aphthous ulcer

An aphthous ulcer, also known as a canker sore, is a type of mouth ulcer which presents as a painful open sore inside the mouth or upper throat characterized by a break in the mucous membrane. Its cause is unknown, but they are not contagious. The condition is also known as aphthous stomatitis (stomatitis is inflammation of the mucous lining), and alternatively as Sutton's Disease, especially in the case of major, multiple, or recurring ulcers.

The term aphtha means ulcer; it has been used for many years to describe areas of ulceration on mucous membranes. Therefore, the term aphtous ulcer is a tautology and the term aphthous stomatitis is preferred. Aphthous stomatitis is a condition characterized by recurrent discrete areas of ulceration that are almost always painful. Recurrent aphthous stomatitis (RAS) can be distinguished from other diseases with similar-appearing oral lesions, such as certain oral bacteria 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 has it, and women are more often affected than men. About 30–40% of patients with recurrent aphthae report a family history.

Classification
Aphthous ulcers are classified according to the diameter of the lesion.

Minor ulceration
Minor aphthous ulcers indicate that the lesion size is between 3 - 10 mm. The appearance of the lesion is that of an erythematous halo with yellowish or grayish color. Pain that affects quality of life is the obvious characteristic of the lesion. When the ulcer is white or grayish, the ulcer will be extremely painful and the affected lip may swell. They may last about 2 weeks.

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 movable non-keratinizing oral surfaces, but the ulcer borders may extend onto keratinized surfaces.

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. Supportive treatment is almost always necessary.

Signs and symptoms


Aphthous ulcers usually begin with a tingling or burning sensation at the site of the future aphthous 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 gray, 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; another symptom is fever. A sore on the gums may be accompanied by discomfort or pain in the teeth.

Causes
The exact cause of many aphthous ulcers is unknown but citrus fruits (e.g., oranges and lemons), physical trauma, stress, lack of sleep, sudden weight loss, food allergies, immune system reactions, and deficiencies in vitamin B12, iron, and folic acid may contribute to their development. Nicorandil and certain types of chemotherapy are also linked to aphthous ulcers. One recent study showed a strong correlation with allergies to cow's milk. Aphthous ulcers are a major manifestation of Behçet disease, and are also common in people with Crohn's disease.

Trauma to the mouth is the most common trigger. Physical trauma, such as that caused by toothbrush abrasions, laceration with sharp or abrasive foods (such as toast or potato chips/crisps), accidental biting (particularly common with sharp canine teeth), after losing teeth, or dental braces can cause aphthous ulcers by breaking the mucous membrane. Other factors, such as chemical irritants or thermal injury, may also lead to the development of ulcers. Using a toothpaste without sodium lauryl sulfate (SLS) may reduce the frequency of aphthous ulcers   One smaller study found no connection between SLS in toothpaste and aphthous ulcers. Celiac disease has been suggested as a cause of aphthous ulcers and some patients benefited from eliminating gluten from their diets.

There is no indication that aphthous ulcers are related to menstruation, pregnancy, and menopause. Smokers appear to be affected less often.

Oral measures

 * Regular use of non-alcoholic mouthwash may help prevent or reduce the frequency of sores. Informal studies suggest that mouthwash may help to temporarily relieve pain.
 * In some cases, switching toothpastes can prevent aphthous ulcers from occurring, with research looking at the role of sodium dodecyl sulfate (sometimes called sodium lauryl sulfate, or with the acronymes SDS or SLS), a detergent found in most toothpastes. Using toothpaste free of this compound has been found in several studies to help reduce the amount, size, and recurrence of ulcers.
 * Dental braces are a common physical trauma that can lead to aphthous ulcers and the dental bracket can be covered with wax to reduce abrasion of the mucosa. Avoidance of other types of physical and chemical trauma will prevent some ulcers, but, since such trauma is usually accidental, this type of prevention is not usually practical.

Nutrition

 * Zinc deficiency has been reported in people with recurrent aphthous ulcers. The few small studies looking into the role of zinc supplementation have mostly reported positive results particularly for those people with deficiency, although some research has found no therapeutic effect.

Treatment
A number of different treatments exist for apthous ulcers including: analgesics, anesthetics agents, antiseptics, anti-inflammatory agents, steroids, sucralfate, tetracycline suspension, and silver nitrate. Amlexanox paste has been found to speed healing and alleviate pain.

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. Active ingredients in the latter generally include benzocaine, benzydamine or choline salicylate, and phenol.

Anesthetic mouthwashes containing benzydamine hydrochloride have not been shown to reduce the number of new ulcers or significantly reduce pain, and evidence supporting the use of other topical anesthetics is very limited, though some individuals may find them effective. In general, their role is limited; their duration of effectiveness is, in general, short and does not provide pain control throughout the day. Such medications may also cause complications in children.

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.

Corticosteroid preparations containing hydrocortisone hemisuccinate or triamcinolone acetonide to control symptoms are effective in treating aphthous ulcers.

The application of silver nitrate will cauterize the sore; a single treatment decreases pain but does not affect healing time though in children it can cause tooth discoloration if the teeth are still developing. The use of tetracycline is controversial, as is treatment with levamisole, colchicine, gamma-globulin, dapsone, estrogen replacement and monoamine oxidase inhibitors.

While commonly used, Magic mouthwash, a combination of a number of ingredients including viscous lidocaine, benzocaine, milk of magnesia, kaolin-pectate, chlorhexidine, or diphenhydramine, has little evidence to support its use. One small-scale study has suggested that Vitamin B12 may be effective in treating recurrent aphthous ulcers, regardless of whether there is a vitamin deficiency present.

Epidemiology
Canker sores are a very common oral lesion. Epidemiological studies show an average prevalence between 15% and 30%. The frequency of canker sores varies from fewer than 4 episodes per year (85% of all cases) to more than one episode per month (10% of all cases) including people suffering from continuous RAS.