Different Types of Mouth Ulcers

mouth ulcers, also called aphthous ulcer or aphthous stomatitis, are small pit lesions (sores) that occur in the mouth. The exact cause is unknown, but they are not contagious.

About 20% of people will develop mouth ulcers at some point in their lives. Mouth sores occur only in the mouth and should not be confused with cold sores caused by the herpes simplex virus.

We tend to think of mouth ulcers as one thing, but there are actually different types, with different characteristics and risk factors.

This article describes the three types of mouth ulcers—including how they look and who they most commonly affect—as well as root causes, symptoms, and treatments.

Types of mouth ulcers

Not all canker sores are the same.Mouth ulcers can be classified as mild, severe or herpes.


Minor mouth ulcers are the most common type, accounting for about 80% of cases. Sizes can vary, but are usually between 1/3″ and 1/2″. They are also sometimes called simple mouth sores.

Although painful, mild mouth sores usually heal completely within two weeks. They can occur spontaneously, usually after a minor oral injury or when you are chronically overworked and exhausted.


Major canker sores that are larger than 1/2 inch tend to last more than two weeks. Minor canker sores are usually round and symmetrical, while major canker sores often have irregular, oddly shaped borders. In rare cases, this type of mouth ulcer can leave a scar.

Severe mouth ulcers are common in people who are immunosuppressed due to chemotherapy or diseases such as HIV. Primary canker sores can also be called complex canker sores. These account for 15% of mouth ulcers.

herpetic aphthous

Canker sores are clusters of several tiny lesions that usually converge to form one large ulcer. Hundreds of pinhead-sized lesions may be involved. Canker sores can last from a week to a month.

Herpes-like mouth ulcers look like a herpes outbreak, but the herpes virus is not involved. The reasons are unclear, but they tend to occur later in life.

Herpetiform oral ulcers account for 5% of aphthous ulcer diagnoses.


Small, round canker sores are the most common type. Major mouth ulcers are large and irregular, and are more common in immunocompromised people. Canker sores cause pinhead-sized clusters of lesions, mostly in older adults.

mouth ulcer symptoms

Mouth ulcers appear in the mouth as round or oval ulcers, usually with raised edges and a yellow, gray, or white center. Mouth ulcers often develop:

  • on the top and tip of the tongue
  • sublingual and floor of mouth
  • on the inside of the cheeks or lips
  • on gingival tissue

A localized burning or tingling sensation in the mouth may occur one to two days before the lesions appear.

Mouth sores can become very painful, especially when eating, drinking, and talking.


Mouth ulcers are usually round, with raised edges and a lighter center. They are usually painful and occur most often on the inner lips, cheeks, or gums, and on or under the tongue.


While we don’t know exactly what causes mouth ulcers, several risk factors have been identified. These include:

  • Minor oral injuries (such as broken teeth, biting cheeks, or wearing ill-fitting dentures)
  • Food sensitivities (especially to coffee, chocolate, strawberries, and spicy and acidic foods)
  • Vitamin deficiencies (especially vitamin B-12, folic acid, iron, and zinc)
  • hormonal changes during menstruation
  • Celiac disease
  • Inflammatory Bowel Disease (IBD)
  • Immunodeficiency diseases such as HIV
  • Helicobacter pylori (bacteria that cause peptic ulcers)
  • emotional stress


There are many risk factors associated with mouth ulcers, including oral injuries, food sensitivities, stress, menstruation, vitamin deficiencies, digestive disorders or infections, and compromised immunity.

Causes and Treatment of Mouth Ulcers


Mouth ulcers do not necessarily require treatment. If they do, they may respond to home remedies, such as salt water and sodium bicarbonate mouthwash. Over-the-counter medications include topical anesthetics such as Anbesol (benzocaine) and antiseptic mouthwashes that contain hydrogen peroxide.

Severe cases may require prescription medication. These include topical steroids like Lidex (fluocinolone), antacids like Carafate (sucralfate), or oral steroids like Decadron (dexamethasone).

One of the best ways to avoid mouth ulcers is to treat the underlying cause. Improper dentures or broken teeth should be repaired. If you have celiac disease or IBD or are prone to ulcers after eating certain foods, changing your diet may help.

Stress management techniques may also help, as stress seems to trigger mouth sores in some people.


Mouth ulcers don’t always require treatment. Depending on their severity and suspicion, treatment may involve antiseptic mouthwashes, numbing agents, prescription antacids, topical or oral steroids, dietary changes, and stress reduction.


Mouth ulcers, also known as aphthous ulcers, are painful, pitted sores in the mouth. There are three different types: small canker sores (the most common type), large canker sores (common in immunosuppressed people), and herpetiform cankers (causing clusters of lesions the size of a pinhead).

Although the causes of mouth ulcers are poorly understood, they have been linked to stress, oral injury, food sensitivities, vitamin deficiencies, menstruation, digestive disorders, and compromised immunity. Mouth ulcers don’t always require treatment, but some people may benefit from topical numbing agents, antiseptic mouthwashes, dietary changes, and oral or topical steroids.

VigorTip words

Mouth sores can make people uncomfortable, make it difficult to eat, or even speak. Most of the time canker sores do not need treatment. However, if your ulcer recurs or if your mouth ulcer has not healed after 14 days, you may need to seek treatment from a dentist or doctor.

Frequently Asked Questions

  • How do you treat severe mouth ulcers?

    If your mouth ulcers are large and painful, your healthcare provider may prescribe an antibacterial mouthwash or corticosteroid ointment. Over-the-counter oral pain gels can also help relieve symptoms.

  • How long does it take for a severe mouth ulcer to heal?

    Severe mouth sores can take four to six weeks to heal. Severe sores may also leave scars.