Canker sores occur inside of the mouth. Canker sores look like small white swellings or sores. The sores may be surrounded by redness. They may hurt or cause mild discomfort. The cause of canker sores is unknown. Researchers suspect viruses, bacteria, or immune system problems cause them. However, other factors including smoking, trauma, allergies, stress, nutritional deficiency, and heredity appear to contribute to the development of canker sores. Additionally, people with certain gastrointestinal disorders, such as ulcerative colitis or Crohn’s disease, may be more prone to canker sores. Canker sores are common and can reappear. They are not contagious.
Cold sores are also called fever blisters or herpes simplex. Cold sores appear on the outside of the mouth on the edges of the lips and the skin below the nose or below the lips. They often occur in groups and appear as fluid-filled blisters. Cold sores can be painful and unsightly. Cold sores are usually caused by the herpes simplex I virus. Cold sore episodes may recur or once infected, a person may just carry the virus. Cold sores are highly contagious.
Leukoplakia occurs inside of the mouth on the tongue, gums, cheeks, or lips. It looks like a thick whitish-colored patch. Leukoplakia results from excess cell growth. It can result from irritants in the mouth including smoking, chewing tobacco, poor fitting dentures, broken teeth, or the habit of chewing on your cheek. Because leukoplakia can lead to cancer, your dentist may take a biopsy (tissue sample) of the site for examination.
Candidiasis is also called moniliasis or oral thrush. It occurs inside of the mouth on the tongue, gums, cheeks, or lips. Candidiasis looks like creamy white-yellow colored areas, red patches, or a combination of both. The affected areas can be painful. Candidiasis is a fungal infection caused by yeast called Candida albicans. It is common among denture wearers and newborns. In some people, it may occur after treatment with certain antibiotics. People with dry mouth are especially susceptible to the fungus. Candidiasis can repeatedly affect people with immune system problems including HIV, AIDS, and cancer.