What causes Mouth sores?
Most mouth sores are cold sores (also called fever blisters), canker sores, or other irritation caused by:
A sharp or broken tooth or poorly fitting dentures Biting your cheek, tongue, or lip Burning your mouth from hot food or drinks Braces Chewing tobacco
Cold sores are caused by the herpes simplex virus and are very contagious. Usually, you will have tenderness, tingling, or burning before the actual sore appears. Cold sores usually begin as blisters and then crust over.
The herpes virus can live in your body for years. It only appears as a mouth sore when something triggers it, such as:
Another illness, especially if there is a fever Hormone changes (such as menstruation) Stress Sun exposure
Canker sores are NOT contagious. They can appear as a single pale or yellow ulcer with a red outer ring, or as a cluster of these sores. The cause of canker sores is not clear, but may be related to:
A virus A temporary weakness in your immune system (for example, from the cold or flu) Hormone changes Irritation Stress Low levels of vitamin B12 or folate
Less commonly, mouth sores can be a sign of an illness, tumor, or reaction to a medication. Such illnesses can be grouped into several broad categories:
Autoimmune disorders (including systemic lupus erythematosus) Bleeding disorders Cancer Infection (such as hand-foot-mouth disease) Weakened immune system -- for example, if you have AIDS or are taking medication after a transplant
Drugs that may cause mouth sores include:
Aspirin Barbiturates (used for insomnia) Chemotherapy drugs for cancer Gold (used for rheumatoid arthritis) Penicillin Phenytoin (used for seizures) Streptomycin Sulfonamides </s>