Sores or localized abnormalities inside the mouth can arise from a number of causes. Mouth sores can occur on the tongue, gums, lips, or inside the cheeks. They may appear as ulcers or red or white patches in the mouth. Bleeding may sometimes occur if ulceration is severe. Bite injuries to the tongue or inside of the cheek are a common cause of mouth sores. Also commonly, mouth sores represent aphthous ulcers, also known as canker sores or aphthous stomatitis. These shallow, painful mouth ulcers often occur in susceptible individuals during times of stress, infection, or changes in immune status. Certain medications (for example, methotrexate [Trexall]) can cause canker sores as well as deficiencies in some B vitamins (1, 2, 6, and 12), iron, folic acid, and zinc. However, irritation, injury, burns, or infection of any of the tissues in the oral cavity can also lead to mouth sores. Sores in the mouth can occur with certain systemic (affecting multiple locations within the body) diseases such as Crohn's disease, Behçet's syndrome, and systemic lupus erythematosus (SLE). Rarely, mouth sores are among the initial signs of oral cancers. Herpes simplex virus infection causes so-called cold sores, which are typically located on the lips, but they can also occur on the gums. Among the sexually transmitted diseases (STDs), the chancres of syphilis can occur as mouth sores.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
Causes of Mouth Sores
Behçet's syndrome is a disease characterized by three symptoms: genital ulcers, recurring mouth ulcers, and...
Bullous pemphigoid is a skin disease that causes blistering eruptions on the skin's surface and sometimes affects the inner...
Burns (First Aid)
Burn types are based on their severity: first-degree burns, second-degree burns, and third-degree burns. First-degree burns are...
Canker sores are a common complaint, and are small ulcers on the inside of the mouth. Canker sores aren't contagious (as opposed...
Chickenpox (chicken pox) is a contagious childhood disease caused by the varicella-zoster virus. Symptoms have an incubation...
Cocaine and Crack Abuse
Cocaine is an addictive stimulant that is smoked, snorted, and injected. Crack is cocaine that comes in a rock crystal that is...
Cold Sores (Nongenital Herpes Simplex Infections)
Herpes simplex infections are common and when they appear around the mouth and lips, people often refer to them as "cold sores"...
Coxsackieviruses may be divided into two groups. Type A causes hand, foot, and mouth disease and conjunctivitis, while type B...
Crohn's Disease (Symptoms, Causes, Diet, Treatment, Life Expectancy)
Crohn's disease is a chronic inflammatory disease, primarily involving the small and large intestine, but which can affect...
Dental injuries range from a chipped or fractured tooth to a knocked out tooth. Treatment depends upon the severity of the dental...
Dry Mouth (Xerostomia)
Dry mouth is a common side effect of many prescription and non-prescription drugs and certain medical conditions. Symptoms of dry...
Graft Versus Host Disease (GVHD)
Graft versus host disease (GVHD) is a condition that happens when immune cells from transplanted donor tissue attack the...
Gum disease is caused by plaque and may result in tooth loss without proper treatment. Symptoms and signs of gum disease...
Hand, Foot, and Mouth Disease
Hand, foot, and mouth syndrome is clinical pattern consisting of a rash on the hands and feet, and in the mouth. Hand, foot, and...
Herpangina is a contagious illness often seen in children. It is caused by a Coxsackievirus or an enterovirus. Symptoms and signs...
Human Immunodeficiency Virus (HIV)
The human immunodeficiency virus (HIV) causes HIV infection and the acquired immunodeficiency syndrome (AIDS). Symptoms and signs...
Is Hand, Foot, and Mouth Disease (HFMD) Contagious?
Hand, foot, and mouth disease (HFMD) is a highly contagious disease caused by several enteroviruses. These viruses are...
Is Thrush Contagious?
Thrush is a fungal infection caused by Candida albicans. An infant with thrush can infect his/her mother with thrush during...
Leukoplakia is a white or gray patch that develops on the tongue or inside the cheek. Causes of Leukoplakia may include...
Lichen planus is a common skin disease that features small, itchy pink or purple spots on the arms or legs. the abnormal areas on...
Lichen sclerosus is a skin disease that causes white spots to form on the skin, which later grow into large, thin, and crinkled...
Lupus (Systemic Lupus Erythematosus or SLE)
Systemic lupus erythematosus is a condition characterized by chronic inflammation of body tissues caused by autoimmune disease....
Melanoma is a type of skin cancer which begins in skin cells called melanocytes and affects more than 53,600 people in the United...
The term oral cancer includes cancer of the mouth (oral cavity) and the back of the mouth (oropharynx). Red and white patches...
Sjögren's syndrome is an autoimmune disease involving the abnormal production of extra antibodies that attack the glands and...
Syphilis in Women
Syphilis is a sexually transmitted disease (STD) caused by a spiral-shaped type of bacteria known as a spirochete. There are...
Thrush (Oral Candidiasis)
Thrush is an infection of the mouth caused by the Candida fungus. Symptoms of thrush include pain or difficulty swallowing, a...
Other Causes of Mouth Sores
- Angular Cheilitis
- Dental Injury
- Erythema Multiforme/Stevens-Johnson Syndrome
- Pemphigus Vulgaris
- Poorly Fitting Braces or Dentures
- Vitamin or Mineral Deficiency