Aphthous stomatitis, or recurrent aphthous stomatitis ( RAS), commonly referred to as a canker sore or salt blister, is a common condition characterized by the repeated formation of benignity and non-contagious (aphthae) in otherwise healthy individuals.
The cause is not completely understood but involves a T cell-mediated immune response triggered by a variety of factors which may include nutritional deficiencies, local Physical trauma, stress, hormonal influences, allergies, genetic predisposition, certain foods, dehydration, some food additives, or some hygienic chemical additives like SDS (common in toothpaste).
These ulcers occur periodically and heal completely between attacks. In the majority of cases, the individual ulcers last about 7–10 days, and ulceration episodes occur 3–6 times per year. Most appear on the non-keratinizing epithelial surfaces in the mouth – i.e. anywhere except the attached gingiva, the hard palate, and the dorsum of the tongue – although the more severe forms, which are less common, may also involve keratinizing epithelial surfaces. Symptoms range from a minor nuisance to interfering with eating and drinking. The severe forms may be debilitating, even causing weight loss due to malnutrition.
The condition is very common, affecting about 20% of the general population to some degree. The onset is often during childhood or adolescence, and the condition usually lasts for several years before gradually disappearing. There is no cure, but treatments such as aim to manage pain, reduce healing time and reduce the frequency of episodes of ulceration.
Ulceration episodes usually occur about 3–6 times per year. However, severe disease is characterized by virtually constant ulceration (new lesions developing before old ones have healed) and may cause debilitating chronic pain and interfere with comfortable eating. In severe cases, this prevents adequate nutrient intake leading to malnutrition and weight loss.
Aphthous ulcers typically begin as (reddened, flat area of mucosa) which develop into ulcers that are covered with a yellow-grey membrane that can be scraped away. A reddish "halo" surrounds the ulcer. The size, number, location, healing time, and periodicity between episodes of ulcer formation are all dependent upon the subtype of aphthous stomatitis.
Aphthous stomatitis has been associated with other autoimmune diseases, namely systemic lupus erythematosus, Behçet's disease and inflammatory bowel diseases. However, common autoantibody are not detected in most patients, and the condition tends to resolve spontaneously with advancing age rather than worsen.
Evidence for the T cell-mediated mechanism of mucosal destruction is strong, but the exact triggers for this process are unknown and are thought to be multiple and varied from one person to the next. This suggests that there are a number of possible triggers, each of which is capable of producing the disease in different subgroups. In other words, different subgroups appear to have different causes for the condition. These can be considered in three general groups, namely primary immuno-dysregulation, decrease of the mucosal barrier and states of heightened antigenic sensitivity (see below). Risk factors in aphthous stomatitis are also sometimes considered as either host-related or environmental.
Stress has effects on the immune system, which may explain why some cases directly correlate with stress. It is often stated that in studies of students with the condition, ulceration is exacerbated during examination periods and lessened during periods of vacation. Alternatively, it has been suggested that oral parafunctional activities such as lip or cheek chewing become more pronounced during periods of stress, and hence the mucosa is subjected to more minor trauma.
Aphthous-like ulceration also occurs in conditions involving systemic immuno-dysregulation, e.g. cyclic neutropenia and human immunodeficiency virus infection. In cyclic neutropenia, more severe oral ulceration occurs during periods of severe immuno-dysregulation, and resolution of the underlying neutropenia is associated with healing of the ulcers. The relative increase in percentage of CD8+ T cells, caused by a reduction in numbers of CD4+ T cells may be implicated in RAS-type ulceration in HIV infection.
The nutritional deficiencies associated with aphthous stomatitis (vitamin B12, folate, and iron) can all cause a decrease in the thickness of the oral mucosa (atrophy).
Local trauma is also associated with aphthous stomatitis, and it is known that trauma can decrease the mucosal barrier. Trauma could occur during injections of local anesthetic in the mouth, or otherwise during dental treatments, frictional trauma from a sharp surface in the mouth such as broken tooth, or from tooth brushing.
Hormonal factors are capable of altering the mucosal barrier. In one study, a small group of females with aphthous stomatitis had fewer occurrences of aphthous ulcers during the luteal phase of the menstrual cycle or with use of the contraceptive pill. This phase is associated with a fall in progestogen levels, mucosal proliferation and keratinization. This subgroup often experiences remission during pregnancy. However, other studies report no correlation between aphthous stomatitis and menstrual period, pregnancy or menopause.
Aphthous stomatitis is less common in people who smoke, and there is also a correlation between habit duration and severity of the condition. Tobacco use is associated with an increase in keratinization of the oral mucosa. In extreme forms, this may manifest as leukoplakia or stomatitis nicotina (smoker's keratosis). This increased keratinization may mechanically reinforce the mucosa and reduce the tendency of ulcers to form after minor trauma, or present a more substantial barrier to microbes and antigens, but this is unclear. Nicotine is also known to stimulate production of adrenal steroids and reduce production of TNF-α, interleukin-1 and interleukin-6. Smokeless tobacco products also seem to protect against aphthous stomatitis. Cessation of smoking is known to sometimes precede the onset of aphthous stomatitis in people previously unaffected, or exacerbate the condition in those who were already experiencing aphthous ulceration. Despite this correlation, starting smoking again does not usually lessen the condition.
In some instances, recurrent mouth ulcers may be a manifestation of an allergic reaction. Possible allergens include certain foods (e.g., chocolate, coffee, strawberries, eggs, nuts, tomatoes, cheese, citrus fruits, , cinnamaldehyde, and highly acidic foods), toothpastes, and mouthwashes. Where dietary allergens are responsible, mouth ulcers usually develop within about 12–24 hours of exposure.
Sodium lauryl sulphate (SLS), a detergent present in some brands of toothpaste and other oral healthcare products, may produce oral ulceration in some individuals. It has been shown that aphthous stomatitis is more common in people using toothpastes containing SLS, and that some reduction in ulceration occurs when a SLS-free toothpaste is used.
Aphthous-like ulceration may occur in association with several systemic disorders (see table). These ulcers are clinically and histopathologically identical to the lesions of aphthous stomatitis, but this type of oral ulceration is not considered to be true aphthous stomatitis by some sources. Some of these conditions may cause ulceration on other mucosal surfaces in addition to the mouth such as the conjunctiva or the genital mucous membranes. Resolution of the systemic condition often leads to decreased frequency and severity of the oral ulceration.
Behçet's disease is a triad of mouth ulcers, genital ulcers and anterior uveitis. The main feature of Behçet's disease is aphthous-like ulceration, but this is usually more severe than seen in aphthous stomatitis without a systemic cause, and typically resembles major or herpetiforme ulceration or both. Aphthous-like ulceration is the first sign of the disease in 25–75% of cases. Behçet's is more common in individuals whose ethnic origin is from regions along the Silk Road (between the Mediterranean and the Far East). It tends to be rare in other countries such as the United States and the United Kingdom. MAGIC syndrome is a possible variant of Behçet's disease, and is associated with aphthous-like ulceration. The name stands for "mouth and genital ulcers with inflamed cartilage" (relapsing polychondritis).
PFAPA syndrome is a rare condition that tends to occur in children. The name stands for "periodic fever, aphthae, pharyngitis (sore throat) and cervical adenitis" (inflammation of the in the neck). The fevers occur periodically about every 3–5 weeks. The condition appears to improve with tonsillectomy or immunosuppression, suggesting an immunologic cause.
In cyclic neutropenia, there is a reduction in the level of circulating in the blood that occurs about every 21 days. Opportunistic infections commonly occur and aphthous-like ulceration is worst during this time.
Hematinic deficiencies (vitamin B12, folic acid and iron), occurring singly or in combination, and with or without any underlying gastrointestinal disease, may be twice as common in people with RAS. However, iron and vitamin supplements only infrequently improve the ulceration. The relationship to vitamin B12 deficiency has been the subject of many studies. Although these studies found that 0–42% of those with recurrent ulcers have a vitamin B12 deficiency, an association with deficiency is rare. Even in the absence of deficiency, vitamin B12 supplementation may be helpful due to unclear mechanisms. Hematinic deficiencies can cause anemia, which is also associated with aphthous-like ulceration.
Gastrointestinal disorders are sometimes associated with aphthous-like stomatitis, e.g. most commonly celiac disease, but also inflammatory bowel disease such as Crohn's disease or ulcerative colitis. The link between gastrointestinal disorders and aphthous stomatitis is probably related to nutritional deficiencies caused by malabsorption. Less than 5% of people with RAS have celiac disease, which can present with a wide range of non-specific symptoms, especially in adults. Sometimes aphthous-like ulcerations can be the only sign of celiac disease. For persons with celiac disease, following a strict gluten-free diet can often end the outbreaks of painful mouth ulcers.
Other examples of systemic conditions associated with aphthous-like ulceration include reactive arthritis, and recurrent erythema multiforme.
Special investigations may be indicated to rule out other causes of oral ulceration. These include to exclude anemia, deficiencies of iron, folate or vitamin B12, or celiac disease. However, the nutritional deficiencies may be latent and the peripheral blood picture may appear relatively normal. Some suggest that screening for celiac disease should form part of the routine work up for individuals complaining of recurrent oral ulceration. Many of the systemic diseases cause other symptoms apart from oral ulceration, which is in contrast to aphthous stomatitis where there is isolated oral ulceration. Patch testing may be indicated if allergies are suspected (e.g. a strong relationship between certain foods and episodes of ulceration). Several drugs can cause oral ulceration (e.g. nicorandil), and a trial substitution to an alternative drug may highlight a causal relationship.
Tissue biopsy is not usually required, unless to rule out other suspected conditions such as oral squamous cell carcinoma. The histopathology appearance is not pathognomonic (the microscopic appearance is not specific to the condition). Early lesions have a central zone of ulceration covered by a fibrinous membrane. In the connective tissue deep to the ulcer there is increased vascularity and a mixed inflammatory infiltrate composed of lymphocytes, and polymorphonuclear leukocytes. The epithelium on the margins of the ulcer shows spongiosis and there are many mononuclear cells in the basal third. There are also lymphocytes and in the connective tissue surrounding deeper blood vessels near to the ulcer, described histologically as "perivascular cuffing".
Occasionally, in females where ulceration is correlated to the menstrual cycle or to birth control pills, progestogen or a change in birth control may be beneficial. Use of nicotine replacement therapy for people who have developed oral ulceration after stopping smoking has also been reported. Starting smoking again does not usually lessen the condition. Trauma can be reduced by avoiding rough or sharp foodstuffs and by brushing teeth with care. If sodium lauryl sulfate is suspected to be the cause, avoidance of products containing this chemical may be useful and prevent recurrence in some individuals. Similarly patch testing may indicate that food allergy is responsible, and the diet modified accordingly. If investigations reveal deficiency states, correction of the deficiency may result in resolution of the ulceration. For example, there is some evidence that vitamin B12 supplementation may prevent recurrence in some individuals.
Within nations, it is more common in higher socioeconomic groups. Males and females are affected in an equal ratio, and the peak age of onset between 10 and 19 years. About 80% of people with aphthous stomatitis first developed the condition before the age of 30. There have been reports of ethnic variation. For example, in the United States, aphthous stomatitis may be three times more common in white-skinned people than black-skinned people.
Aphthous stomatitis was once thought to be a form of recurrent herpes simplex virus infection, and some clinicians still refer to the condition as "herpes" despite this cause having been disproven.
The informal term "canker sore" is sometimes used, mainly in North America, either to describe this condition generally, or to refer to the individual ulcers of this condition, or mouth ulcers of any cause unrelated to this condition. The origin of the word "canker" is thought to have been influenced by Latin, Old English, Middle English and Old North French. In Latin, cancer translates to "malignant tumor" or literally "crab" (related to the likening of sectioned tumors to the limbs of a crab). The closely related word in Middle English and Old North French, chancre, now more usually applied to syphilis, is also thought to be involved. Despite this etymology, aphthous stomatitis is not a form of cancer but rather entirely benign.
An aphtha (plural aphthae) is a non specific term that refers to an ulcer of the mouth. The word is derived from the Greek word aphtha meaning "eruption" or "ulcer". The lesions of several other oral conditions are sometimes described as aphthae, including Bednar's aphthae (infected, traumatic ulcers on the hard palate in infants), oral candidiasis, and foot-and-mouth disease. When used without qualification, aphthae commonly refers to lesions of recurrent aphthous stomatitis. Since the word aphtha is often taken to be synonymous with ulcer, it has been suggested that the term "aphthous ulcer" is redundant, but it remains in common use. Stomatitis is also a non-specific term referring to any inflammatory process in the mouth, with or without oral ulceration. It may describe many different conditions apart from aphthous stomatitis such as angular stomatitis.
The current most widely used medical term is "recurrent aphthous stomatitis" or simply "aphthous stomatitis". Historically, many different terms have been used to refer to recurrent aphthous stomatitis or its sub-types, and some are still in use. Mikulicz's aphthae is a synonym of minor RAS, named after Jan Mikulicz-Radecki. Synonyms for major RAS include Sutton's ulcers (named after Richard Lightburn Sutton), Sutton's disease, Sutton's syndrome and periadenitis mucosa necrotica recurrens. Synonyms for aphthous stomatitis as a whole include (recurrent) oral aphthae, (recurrent) aphthous ulceration and (oral) aphthosis.
In traditional Chinese medicine, claimed treatments for aphthae focus on clearing heat and nourishing Yin.
Rembrandt Gentle White toothpaste did not contain sodium lauryl sulfate, and was specifically marketed as being for the benefit of "canker sore sufferers". When the manufacturer Johnson & Johnson discontinued the product in 2014, it caused a backlash of anger from long-term customers, and the toothpaste began to sell for many times the original price on the auction website eBay.
Signs and symptoms
Causes
Immunity
Mucosal barrier
Antigenic sensitivity
Systemic disease
Diagnosis
Classification
Minor aphthous ulceration
Major aphthous ulceration
Herpetiform ulceration
RAS type ulceration
Treatment
Medication
Orabase (often combined with triamcinolone). Benzydamine hydrochloride mouthwash or spray, Amlexanox paste, viscous lidocaine, diclofenac in hyaluronan. Doxycycline, tetracycline, minocycline, chlorhexidine gluconate, triclosan. Hydrocortisone sodium succinate. Beclomethasone dipropionate aerosol, fluocinonide, clobetasol, betamethasone sodium phosphate, dexamethasone. Prednisolone, colchicine, pentoxifylline, azathioprine, thalidomide, dapsone, mycophenolate mofetil, adalimumab, vitamin B12, Clofazimine, Levamisole, Montelukast, Sulodexide,
Other
Prognosis
Epidemiology
History, society and culture
See also
External links
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