There are several different factors commonly recognized as mouth ulcer causes. Many times an ulcer, also known as a canker sore, may arise from some type of irritation or injury in the mouth. A variety of infections are known to cause them, particularly if one's immune system is compromised. Some medications tend to cause ulcers to form, as well as certain nutritional deficiencies. They are also often associated with several types of chronic diseases.
Damage to the gums, tongue, or inside of the lips is one of the most common mouth ulcer causes. They often form at the site of cuts or abrasions caused by such things as the sharp edge of a tooth, braces, or overly hard brushing. The surfaces inside the mouth can also become dry or irritated due to substances such as alcohol, acidic foods, or mouthwashes and toothpastes containing sodium lauryl sulfate, creating the ideal environment for a canker sore to grow.
Infections are another of the common mouth ulcer causes. Certain viruses, including herpes simplex, varicella zoster, and coxsackie A are often associated with sores in the mouth. Bacterial infections can also be to blame; examples include mycobacterium tuberculosis and treponema pallidum. In some cases, mouth ulcers may come from fungal or protozoan infections. Sores from infection may have a greater tendency to affect those whose immune systems are not strong, including people with HIV, undergoing chemotherapy, or under constant stress.
People taking certain types of medication may tend to get mouth ulcers. Those who use inhaled corticosteroids may be prone to them, particularly if they do not rinse their mouths afterward. Use of NSAIDs and beta blockers has also been associated with higher risk of canker sores. Those undergoing chemotherapy or using methotrexate also often tend to develop them.
Nutritional deficiency may also increase the chance of getting a mouth ulcer. People who are not getting enough vitamin C or B12 may be prone to them. It is also important to get enough of minerals such as zinc, iron, and folic acid to prevent canker sores from forming.
A number of chronic illnesses are also commonly known as mouth ulcer causes. Those with Behcet's disease often develop sores in their mouths. Diseases of the digestive system such as Crohn's disease may be to blame. People with celiac disease, an intolerance of foods containing gluten, can also suffer from them.