Mouth sores are common, and can affect people of all ages. While many mouth sores are harmless, some indicate more serious problems. Treatment depends on the type of mouth sore you have.
Mouth sores are painful lesions that form in your oral soft tissues. They may appear on your lips, gums, tongue, cheeks, the floor of your mouth or the roof of your mouth.
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The term “mouth sore” can describe a number of different conditions affecting the oral cavity. There are several types of mouth sores, including:
Mouth sores can affect anyone, but some are more likely to occur during a certain time in life. For example, while thrush and gingivostomatitis are most common in children, leukoplakia and lichen planus are more common in older adults.
Cold sores and canker sores are among the most common types of mouth lesions. About 20% of people will develop canker sores at some point in their lives. And while over half of Americans have been infected with the virus that causes cold sores, only 20 to 40% of people develop cold sores as a result.
Exact symptoms can vary depending on the type of mouth sore you have. In most cases, the lesions will cause redness, pain and inflammation. You may also experience:
There are a number of things that can lead to mouth sores. Causes range from common injuries to serious health conditions. Common mouth sore causes include:
There are also many diseases and health conditions that can cause mouth sores to develop, including:
People who are undergoing cancer treatment may develop mouth sores as well. This is especially true for individuals receiving radiation therapy to the head or neck.
It depends on what type of mouth sore you have. Cold sores are contagious, but canker sores aren’t. If you’re unsure about the type of mouth sore you have, contact your healthcare provider.
Contagious mouth sores — like cold sores caused by the herpes simplex virus — spread through saliva and close contact. If you think you have a cold sore in your mouth, avoid kissing and sharing food, beverages and utensils with others.
Cold sores are usually contagious for up to 15 days. When all symptoms have subsided — including blistering and scabbing — you are no longer considered contagious.
While viruses are the most common infectious cause of mouth sores, bacteria can cause oral lesions too. For example, cold sores are caused by the herpes simplex virus. But mouth sores like gingivostomatitis can be caused by certain bacteria, such as streptococcus and actinomyces.
Some sores only form on the soft tissues inside the mouth. Other sores — like cold sores caused by the herpes simplex virus — usually appear in the corners of the mouth or on the lips.
Most mouth sores can be diagnosed with a visual examination. However, your healthcare provider may order a blood test or biopsy if your condition is severe.
In most cases, a dentist can appropriately diagnose and treat a mouth sore. However, if you have recurrent mouth sores that are associated with a medical condition, it’s best to see your primary care physician or an ear, nose and throat specialist.
You can have a mouth infection without developing mouth sores. If you notice any other unusual symptoms, such as bleeding, swelling or tenderness, call your healthcare provider right away.
Your healthcare provider may prescribe medication to ease your symptoms. Mouth sore treatments may include:
Additionally, there are things you can do at home to reduce discomfort:
When you have a mouth sore, try eating cold foods like sherbet, sorbet, ice pops or ice chips. This may help soothe the area. Avoid foods that are hot, spicy or salty — and steer clear of citrus-based foods like oranges, pineapple and tomato sauce.
While you can’t prevent mouth sores altogether, there are some things you can do to reduce your risk. For example:
Most people who develop mouth sores experience no long-term effects. But some individuals notice that sores reappear from time to time. These outbreaks are more likely if you’ve been under stress or have a weakened immune system. If you have recurrent mouth sores, talk to your healthcare provider. They can determine if your lesions are related to an underlying condition.
Not all mouth sores need immediate medical attention. But you should call your healthcare provider if you have lesions larger than a half an inch in diameter or if your mouth sore is accompanied by:
While not a common symptom of COVID, mouth sores have been reported in people with the virus. More research is needed to determine if the oral lesions were caused by coronavirus or if they are secondary symptoms.
A note from Cleveland Clinic
Most mouth sores are harmless, but they can be quite painful. Fortunately, treatments are available to help reduce discomfort. It’s important to have an evaluation with your healthcare provider if you have any unusual symptoms or if your mouth sores haven’t healed in three weeks. This can help rule out any serious health concerns and detect any issues early on.
Last reviewed by a Cleveland Clinic medical professional on 09/07/2021.
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