Mouth Sores

There are many types of mouth sores. Some, such as canker sores, are minor and can clear up on their own. Others, such as sores that develop from health conditions such as oral cancer, are more severe. Mouth sores can form on the cheeks, gums, tongue, floor and roof of the mouth; and lips.

This article discusses the possible causes of and treatments for various types of mouth sores.

Symptoms of Mouth Sores

The symptoms that develop along with mouth sores depend on the type and cause. Some of the symptoms that can come with mouth sores include:

• Burning or tingling sensations in the mouth (specifically near the sore)
• Having difficulty eating foods that are spicy or salty
• Stinging
• Bleeding
• Difficulty swallowing
• Breaks in the skin that do not heal (ulcerations)
• Sores that do not heal
• Unintentional weight loss
• Loose teeth
• Red or white patches in the mouth or on the tongue

Mouth sores can present with some or all of the above symptoms.

Causes of Mouth Sores

There are several health conditions that can cause mouth sores to develop, including:

• Idiopathic: Idiopathic mouth sores occur but are not linked to an underlying health condition. Canker sores are an example of this type of mouth sore.
• Autoimmune diseases: Some autoimmune diseases—such as Crohn’s disease, lichen planus, and systemic lupus erythematosus—can cause sores to develop in the mouth.
• Trauma: Trauma such as biting your cheek or burning your mouth can cause a mouth sore. In some cases, trauma from dental tools can also cause a mouth sore.
• Hematologic: Hematologic disorders are disorders of the blood. Anemia and neutropenia are blood disorders that can cause mouth sores.
• Fever syndromes: Certain disorders that cause a fever without an infection (fever syndromes) can cause mouth sores.
• Cancer: Certain types of cancers can cause painful mouth sores.
• Food allergies: Some food allergies are a common cause of mouth sores.
• Vesiculobullous disorders: These conditions only affect the mouth and are characterized by the mouth sores they cause.
• Nutrient deficiencies: Being deficient in nutrients like iron, folate, zinc, or several B vitamins can lead to mouth sores.
• Viral infections: Viral infections such as herpes simplex, shingles, Coxsackie A, Epstein-Barr, and human immunodeficiency virus (HIV) can cause sores to develop in the mouth. COVID-19 has also been shown to cause oral lesions in some people.
• Bacterial infections: Syphilis and tuberculosis are bacterial infections that can cause mouth sores.
• Inherited disorders: Epidermolysis bullosa and chronic granulomatous disease can cause sores to develop in the mouth.
• Oral infections: Some oral infections, such as gingivostomatitis, cause mouth sores. Gingivostomatitis is caused by a primary infection, such as herpes simplex.

What Medications Can Cause Mouth Sores?

There are several types of drugs that can cause oral sores or ulcerations, including:

• Immunosuppressants (drugs that suppress the action of the immune system)
• Blood pressure medications
• Some inhalers that treat COPD or asthma
• Drugs used to treat specific heart issues caused by blood clots
• Medications designed to restore blood flow by opening blood vessels
• Protease inhibitors (a type of HIV medication)
• Some antibiotics
• Non-steroidal anti-inflammatory drugs (NSAIDs)
• Some antiviral medications
• Chemotherapy

How to Treat Mouth Sores

Treating mouth sores means treating the cause. Idiopathic mouth sores will typically clear up on their own within one to three weeks.

If you are having a lot of pain or get recurrent idiopathic mouth sores, you can try numbing gels, antiseptic mouthwashes, or anti-inflammatory medications to ease pain and promote healing.   

Mouth sore treatment according to the underlying cause includes:

• Autoimmune diseases: Treatment for autoimmune disorders depends on many factors, such as the type of disease and the person receiving treatment. Some options include corticosteroids, biologics, immunosuppressant medications, and disease-modifying anti-inflammatory drugs.
• Trauma: Depending on the extent of the trauma, you may have to wait for the sore to heal on its own. You can help the healing process by rinsing your mouth out with saltwater daily, eating soft foods, and using a topical pain reliever made specifically for your mouth.
• Hematologic: Different treatments are required for different blood disorders. Blood transfusions, medications designed to thicken or thin the blood, and aspirin are all possible options for treating blood disorders.
• Fever syndromes: There is no one treatment option for fever syndromes. Some immune system-stimulating drugs, such as interleukin 1, have been used to treat these disorders.
• Vesiculobullous disorders: Some vesiculobullous diseases will go away and return on their own. There are some treatments, such as corticosteroids, antibiotics, and immunosuppressants.
• Nutrient deficiencies: Eating more nutrient-rich foods or using supplements that bridge any gaps in nutrition can help address deficiencies.
• Viral infections: Viral infections do not always require treatment. If they do, antivirals will be used.
• Bacterial infections: Bacterial infections are treated with antibiotics. The length and type of antibiotics used will depend on the severity of the illness and the bacteria causing the infection.
• Inherited disorders: There is no cure for inherited diseases, but they can be treated using a variety of different therapies, including antidepressants, epilepsy medications, and acetaminophen (Tylenol) for pain.
• Oral infections: Oral infections have a variety of treatments, including numbing gel and over-the-counter (OTC) pain relievers, antibiotics, and mouth rinses.

Are There Tests to Diagnose Mouth Sores?

There are several different tests used for diagnosing mouth sores because there are many possible causes.

To determine what is causing the mouth sores, your healthcare provider will look at the inside of your mouth and assess the sore(s). They will also you about any other symptoms you are experiencing and about any medications you are on. Other factors that are considered in the diagnostic process include:

• How long you’ve had the sores
• If the sores heal and then come back again
• Where the sores are in the mouth

Your provider may do other tests if they think an underlying health condition is causing the sores based on your other symptoms. Usually, this will include doing blood tests.

When to See a Healthcare Provider

You cannot self-diagnose a mouth sore. Your healthcare provider needs to look at the sores to figure out what they are being caused by. This is especially important if you have mouth sores that do not heal in a few weeks or continue to come back after they do heal.

You should also see your provider if you are experiencing any symptoms along with the sores, such as pain and difficulty eating or swallowing. You should also see a provider if you think you have an infection or have symptoms of an infection.

Recent chemotherapy, radiation, or starting a new medication, are other factors that would prompt a call to your provider.

Summary

Mouth sores can develop anywhere in the mouth, including the tongue, inside the cheeks, the roof of the mouth, underneath the tongue, and the lips. While many types of mouth sores are harmless and only cause mild pain or irritation, others can be signs of more severe health conditions.

Typically, mouth sores that develop because of a disorder will also come with other symptoms such as fever, difficulty swallowing, or unintentional weight loss.

It's important to see your provider to find out for sure what is causing your mouth sores. That way, you can address any underlying condition that's causing them instead of leaving them to heal on their own when they require treatment.

A Word from Verywell

There are many causes of mouth sores. While not all of them are serious, it's important to find out why they are happening—especially if they don't heal on their own or keep coming back. Your provider can do tests to find out what's causing your mouth sores and recommend the best treatment.