Causes of Mouth Sores

Causes of Mouth Sores

by Alex Hirsch (SU)

Mouth sores are growths or lesions that can appear on the tongue, lips, gums, roof of the mouth, and inside the cheeks. They are often unsightly and painful, and they can make anyone feel self-conscious. External mouth sores are also called canker sores or cold sores.

Some mouth sores disappear on their own, depending on the cause; however, there are some that require medical treatment. If the sore doesn’t go away within two weeks, have it checked by a dentist.

Why Do Mouth Sores Develop?

Let’s talk about what causes mouth sores and what you can do about them:

Mouth Injury 

A mouth sore could be the result of an injury or irritation. You can sometimes bite the inside of your cheek. If you wear dentures, the materials may scratch the inner cheek. Tongue piercings can also cause injury to the soft tissues of the mouth.


Some types of prescription medication may also cause mouth sores as a side effect. One major example is antibiotics, which are used to treat infections but can cause the proliferation of Candida albicans in the mouth.

Spicy and Acidic Foods 

Very spicy food and acidic drinks can cause mouth sores to develop, especially if there’s already a vulnerability – such as a cut or a tiny infection around the mouth. Lemon drinks, cider drinks, and spicy soup are a few examples of foods that can exacerbate mouth sores.


This is a common cause of mouth lesions, since smoking dries the mouth tissue and compromises your immune system. The toxic chemicals in a cigarette are carcinogenic, which can increase your risk of developing oral cancer.

Viral Infection

An infection caused by a virus is one of the most common causes of mouth sores. The herpes simplex virus, for instance, causes “cold sores” to develop on the lip and mouth area. The varicella-zoster virus causes painful sores to develop on the inside of your mouth, typically on just one side.

Bacterial Infection 

Another common cause of mouth sores is a bacterial infection. Examples are gonorrhea and syphilis. Bacterial infection from the teeth and gums can also spread and cause mouth sores.

Cancer or Cancer Treatment 

Mouth sores may be a symptom of oral cancer. Treatments for cancer, such as chemotherapy drugs and radiation, can also cause mouth sores to develop. This type of ulcerative lesion in the mouth is called oral mucositis.

Mouth Health in Greater Las Vegas

If your mouth sores refuse to go away after two weeks, have a dentist examine your mouth so you can get started on effective treatment as soon as possible. Here at Dedicated Dental, our experienced dental team is dedicated to restoring your oral health and maintaining it for a lifetime.

Ours is a friendly and approachable staff, and we take our time with our patients and explain in detail your diagnosis and your treatment plans as necessary. We encourage you to take active participation in your oral care, and the first step toward that effort is seeking an evaluation by a skilled dentist. 

To schedule a consultation, call Dedicated Dental today at (702) 566-5509 or fill out our appointment request form online now. We look forward to seeing you.