Due to various factors (saliva, relative thinness of oromucosa, trauma from teeth, chewing, etc.), vesicles and bullae which form on the mucous membranes of the oral cavity tend to be fragile and quickly break down to leave ulcers. Aphthous stomatitis and local trauma are very common causes of oral ulceration; the many other possible causes are all rare in comparison. Traumatic ulceration A "crop" of trauma-induced ulcers on the labial mucosa Most<unk> s that are not associated with recurrent aphthous stomatitis are caused by local trauma. The mucous membrane lining of the<unk>  is thinner than the skin, and easily damaged by mechanical, thermal (heat/cold), chemical, or electrical means, or by irradiation. Mechanical A small ulcer on the frenum on the lower inside lip Common causes of oral ulceration include rubbing on sharp edges of teeth, fillings, crowns, false teeth (dentures), or braces (orthodontic appliances), or accidental biting caused by a lack of awareness of painful stimuli in the<unk>  (e.g., following local anesthetic used during dental treatment, which the person becomes aware of as the anesthetic wears off). Eating hard foods (e.g., potato chips) can damage the lining of the<unk> . Some people cause damage inside their<unk> s themselves, either through an absentminded habit or as a type of deliberate self-harm (factitious ulceration). Examples include biting the cheek, tongue, or lips, or rubbing a fingernail, pen, or toothpick inside the<unk> . Tearing (and subsequent ulceration) of the upper labial frenum may be a sign of child abuse (non-accidental injury). Iatrogenic ulceration can also occur during dental treatment, where incidental abrasions to the soft tissues of the<unk>  are common. Some dentists apply a protective layer of petroleum jelly to the lips before carrying out dental work to minimize this. The lingual frenum is also vulnerable to ulceration by repeated friction during oral sexual activity ("cunnilingus tongue"). Rarely, infants can ulcerate the tongue or lower lip with the teeth, termed Riga-Fede disease. Thermal and electrical burn Thermal burns usually result from placing hot food or beverages in the<unk> . This may occur in those who eat or drink before a local anesthetic has worn off. The normal painful sensation is absent and a burn may occur. Microwave ovens sometimes produce food that is cold externally and very hot internally, and this has led to a rise in the frequency of intra-oral thermal burns. Thermal food burns are usually on the palate or posterior buccal mucosa, and appear as zones of erythema and ulceration with necrotic epithelium peripherally. Electrical burns more commonly affect the oral commissure (corner of the<unk> . The lesions are usually initially painless, charred and yellow with little bleeding. Swelling then develops and by the fourth day following the burn the area becomes necrotic and the epithelium sloughs off. Electrical burns in the<unk>  are usually caused by chewing on live electrical wiring (an act that is relatively common among young children). Saliva acts as a conducting medium and an electrical arc flows between the electrical source and the tissues, causing extreme heat and possible tissue destruction. Chemical injury Caustic chemicals may cause ulceration of the oral mucosa if they are of strong-enough concentration and in contact for a sufficient length of time. The holding of medication in the<unk>  instead of swallowing it occurs mostly in children, those under psychiatric care, or simply because of a lack of understanding. Holding an aspirin tablet next to a painful tooth in an attempt to relieve pulpitis (toothache) is common, and leads to epithelial necrosis. Chewable aspirin tablets should be swallowed, with the residue quickly cleared from the<unk> . Other caustic medications include eugenol and chlorpromazine. Hydrogen peroxide, used to treat gum disease, is also capable of causing epithelial necrosis at concentrations of 1–3%. Silver nitrate, sometimes used for pain relief from aphthous ulceration, acts as a chemical cauterant and destroys nerve endings, but the mucosal damage is increased. Phenol is used during dental treatment as a cavity sterilizing agent and cauterizing material, and it is also present in some over-the-counter agents intended to treat aphthous ulcerations. Mucosal necrosis has been reported to occur with concentrations of 0.5%. Other materials used in endodontics are also caustic, which is part of the reason why use of a rubber dam is now recommended. Irradiation As a result of radiotherapy to the<unk> , radiation-induced stomatitis may develop, which can be associated with mucosal erosions and ulceration. If the salivary glands are irradiated, there may also be xerostomia (dry<unk> , making the oral mucosa more vulnerable to frictional damage as the lubricating function of saliva is lost, and mucosal atrophy (thinning), which makes a breach of the epithelium more likely. Radiation to the bones of the jaws causes damage to osteocytes and impairs the blood supply. The affected hard tissues become hypovascular (reduced number of blood vessels), hypocellular (reduced number of cells), and hypoxic (low levels of oxygen). Osteoradionecrosis is the term for when such an area of irradiated bone does not heal from this damage. This usually occurs in the mandible, and causes chronic pain and surface ulceration, sometimes resulting in non-healing bone being exposed through a soft tissue defect. Prevention of osteradionecrosis is part of the reason why all teeth of questionable prognosis are removed before the start of a course of radiotherapy. Aphthous stomatitis An aphthous ulcer on the labial mucosa (note erythematous "halo" surrounding lesion) Aphthous stomatitis (also termed recurrent aphthous stomatitis, RAS, and commonly called "canker sores") is a very common cause of oral ulceration. 10–25% of the general population suffer from this non-contagious condition. Three types of aphthous stomatitis exists based on their appearance, namely minor, major and herpetiform major aphthous ulceration. Minor aphthous ulceration is the most common type, presenting with 1–6 small (2-4mm diameter), round/oval ulcers with a yellow-grey color and an erythematous (red) "halo". These ulcers heal with no permanent scarring in about 7–10 days. Ulcers recur at intervals of about 1–4<unk> s. Major aphthous ulceration is less common than the minor type, but produces more severe lesions and symptoms. Major aphthous ulceration presents with larger (>1 cm diameter) ulcers that take much longer to heal (10–40 days) and may leave scarring. The minor and major subtypes of aphthous stomatitis usually produce lesions on the non-keratinized oral mucosa (i.e. the inside of the cheeks, lips, underneath the tongue and the floor of<unk> , but less commonly major aphthous ulcers may occur in other parts of the<unk>  on keratinized mucosal surfaces. The least common type is herpetiform ulceration, so named because the condition resembles primary herpetic gingivostomatitis. Herpetiform ulcers begin as small blisters (vesicles) which break down into 2-3mm sized ulcers. Herpetiform ulcers appear in "crops" sometimes hundreds in number, which can coalesce to form larger areas of ulceration. This subtype may cause extreme pain, heals with scarring and may recur frequently. The exact cause of aphthous stomatitis is unknown, but there may be a genetic predisposition in some people. Other possible causes include hematinic deficiency (folate, vitamin B, iron), stopping smoking, stress, menstruation, trauma, food allergies or hypersensitivity to sodium lauryl sulphate (found in many brands of toothpaste). Aphthous stomatitis has no clinically detectable signs or symptoms outside the<unk> , but the recurrent ulceration can cause much discomfort to sufferers. Treatment is aimed at reducing the pain and swelling and speeding healing, and may involve systemic or topical steroids, analgesics (pain killers), antiseptics, anti-inflammatories or barrier pastes to protect the raw area(s). Infection + Infectious causes of oral ulceration Agent Example(s) Viral chickenpox, hand, foot and<unk>  disease, herpangina, herpetic stomatitis, human immunodeficiency virus, infectious mononucleosis Bacterial acute necrotizing ulcerative gingivitis, gangrenous stomatitis, syphilis, tuberculosis Fungal blastomycosis, cryptococcosis, histoplasmosis, paracoccidioidomycosis Parasitic leishmaniasis Many infections can cause oral ulceration (see table). The most common are herpes simplex virus (herpes labialis, primary herpetic gingivostomatitis), varicella zoster (chicken pox, shingles), and coxsackie A virus (hand, foot and<unk>  disease). Human immunodeficiency virus (HIV) creates immunodeficiencies which allow opportunistic infections or neoplasms to proliferate. Bacterial 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 streptococci, Neisseria, Actinomyces, spirochetes, and Bacteroides species can prolong the ulcerative process. Fungal causes include Coccidioides immitis (valley fever), Cryptococcus neoformans (cryptococcosis), and Blastomyces dermatitidis ("North American Blastomycosis"). Entamoeba histolytica, a parasitic protozoan, is sometimes known to cause<unk> s through formation of cysts. Epstein-Barr virus-positive mucocutaneous ulcer is a rare form of the Epstein-Barr virus-associated lymphoproliferative diseases in which infiltrating, Epstein-Barr virus (i.e. EBV)-infected B cells cause solitary, well-circumscribed ulcers in mucous membranes and skin. Drug-induced Many drugs can cause<unk> s as a side effect. Common examples are alendronate (a bisphosphonate, commonly prescribed for osteoporosis), cytotoxic drugs (e.g. methotrexate, i.e. chemotherapy), non-steroidal anti-inflammatory drugs, nicorandil (may be prescribed for angina) and propylthiouracil (e.g. used for hyperthyroidism). Some recreational drugs can cause ulceration, e.g. cocaine. Malignancy Advanced oral cancer (T4 N2 M0, stage 4). Note rolled margins of central ulcer and surrounding areas of
Mouth ulcer
Geographic tongue
Stercoral ulcer
Dental abscess
Callous ulcer
Pouchitis
Skin fissure
Tropical ulcer