An oral ulcer, or, in American English, canker sore is an open sore inside the mouth, or rarely a break in the mucous membrane or the epithelium on the lips or surrounding the mouth. The types of ulcers are diverse, with a multitude of associated causes including: physical abrasion, acidic fruit, infection, other medical conditions, medications, and cancerous and nonspecific processes. Once formed, the ulcer may be maintained by inflammation and/or secondary infection. Two common types are aphthous ulcers (“canker sores”) and cold sores (fever blisters, oral herpes). Cold sores around the lip are caused by viruses.
Mouth ulcer is a very common oral lesion. Epidemiological studies show an average prevalence between 15% and 30%. Mouth ulcers tend to be more common in women and those under 45. Mouth ulcers occur most frequently among 16-25 year olds, and they rarely occur in anyone over 55.The frequency of mouth ulcers 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.
Causes:: Minor physical injuriesTrauma to the mouth is a common cause of ulcers. A sharp edge of a tooth, accidental biting (this can be particularly common with sharp canine teeth, or Wisdom teeth), sharp, abrasive, or excessively salty food, hot drinks, poorly fitting dentures, dental braces or trauma from a toothbrush may injure the mucosal lining of the mouth resulting in an ulcer. These ulcers usually heal at a moderate speed if the source of the injury is removed (for example, if poorly fitting dentures are removed or replaced)
These ulcers also commonly occur after dental work, when incidental abrasions to the soft tissues of the mouth are common. A dentist can apply a protective layer of petroleum jelly before carrying out dental work in order to minimize the number of incidental injuries to the soft mucosa tissues.
Chemical injuriesChemicals such as aspirin or alcohol that are held or that come in contact with the oral mucosa may cause tissues to become necrotic and slough off creating an ulcerated surface. Sodium lauryl sulfate (SLS), one of the main ingredients in most toothpastes, has been implicated in increased incidence of oral ulcers.
ChemotherapyMouth Ulcers are common as a side effect of chemotherapy for some people and due to the lowered immune system caused by chemotherapy it is essential that oral hygene is given particular care to avoid further infection.
Smoking CessationIt is fairly common for smokers to experience multiple mouth ulcers within a week of cessation. The duration varies between individuals, and can range from a month to years. Oral nicotine supplements have shown some reduction in the occurrence.[8][9]
InfectionViral, fungal and bacterial processes can lead to oral ulceration. One way to contract pathogenic oral ulcerations is to touch your chapped lips without having washed your hands first. The reason that this happens is that the bacteria from your hands sinks into the tiny, open cuts caused by your chapped lips.
ViralThe most common is Herpes simplex virus which causes recurrent herpetiform ulcerations preceded by usually painful multiple vesicles which burst. Varicella Zoster (chicken pox, shingles), Coxsackie A virus and its associated subtype presentations, are some of the other viral processes that can lead to oral ulceration. HIV creates immunodeficiencies which allow opportunistic infections or neoplasms to proliferate.
BacterialBacterial processes leading to ulceration can be caused by Mycobacterium tuberculosis (tuberculosis) and Treponema pallidum (syphilis).
Opportunistic activity by combinations of otherwise normal bacterial flora, such as aerobic streptococi, Neisseria, Actinomyces, spirochetes, and Bacteroides species can prolong the ulcerative process.
FungalCoccidioides immitis (valley fever), Cryptococcus neoformans (cryptococcosis), Blastomyces dermatitidis (“North American Blastomycosis”) are some of the fungal processes causing oral ulceration
ProtozoansEntamoeba histolytica, a parasitic protozoan, is sometimes known to cause mouth ulcers through formation of cysts.
Immune systemMany researchers view the causes of aphthous ulcers as a common end product of many different disease processes, each of which is mediated by the immune system.
Aphthous ulcers are thought to form when the body becomes aware of and attacks chemicals which it does not recognize.
ImmunodeficiencyRepeat episodes of mouth ulcers can be indicative of an immunodeficiency, signaling low levels of immunoglobulin in the oral mucous membranes. Chemotherapy, HIV, and mononucleosis are all causes of immunodeficiency with which oral ulcers become a common manifestation.
AutoimmunityAutoimmunity is also a cause of oral ulceration. Mucous membrane pemphigoid, an autoimmune reaction to the epithelial basement membrane, causes desquamation/ulceration of the oral mucosa.
AllergyContact with allergens such as amalgam can lead to ulcerations of the mucosa.
DietaryVitamin C deficiencies may lead to scurvy which impairs wound healing, which can contribute to ulcer formation.[3] Similarly deficiencies in iron vitamin B12, zinc[have been linked to oral ulceration.
Acidic food such as citrus fruit may cause mouth ulcers.
PreventionFor trauma related cases, avoiding the offending source will prevent ulceration, but since such trauma is usually accidental, this type of prevention is not usually practical
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