Aphthous ulcers

What are aphthous ulcers?

Aphthous ulcers (aphthae, or canker sores) are ulcers that form on the mucous membranes of the mouth or genitals. The most common type of an aphthous ulcer is recurrent minor aphthous ulcer (recurrent aphthous stomatitis). Recurrent aphthous ulceration is also be known as aphthous stomatitis.

Aphthous ulcers are typically recurrent round or oval sores or ulcers that occur inside the mouth on areas where the skin is not tightly bound to the underlying bone (e.g. on the inside of the lips and cheeks or underneath the tongue). They may also appear on the genitals (Lipschutz ulcer), particularly if there is an associated condition such as Behcet disease or HIV.

Aphthous ulceration

Images of vulval ulcers

What causes aphthous ulcers?

The exact reason why aphthous ulcers develop is not yet clearly defined. Current thinking is that the immune system has been disturbed by some external factor and this results in the development of aphthous ulcers. Also, approximately 40% of people who get ulcers have a family history of aphthous ulcers.

Some factors that seem to trigger outbreaks of ulcers include:

• Emotional stress and lack of sleep
• Mechanical trauma, for example self-inflicted bite
• Nutritional deficiencies, particularly vitamins B, iron, and folic acid
• Certain foods including chocolate
• Certain toothpastes
• Menstrual cycle
• Certain medications, including nicorandil, given for angina

Aphthous ulcers are commonly present in certain medical conditions. Many of these conditions are associated with impaired immune systems and include Behcet disease, HIV/AIDS, gluten-sensitive enteropathy, Crohn disease and inflammatory bowel disease.

Who is at risk of aphthous ulcers?

Anyone can get aphthous ulcers; 20% of the population have them at least occasionally. They usually first appear in childhood or adolescence, and more commonly in females than males.

Interestingly, smoking may be protective against aphthae, even though smoking makes many oral conditions worse.

What are the signs and symptoms of aphthous ulcers?

There are basically 3 types of aphthous ulcers:

• Recurrent minor aphthous ulcers, which occur in up to 80% of aphthous ulcer cases. They are usually less than 5mm in diameter and heal within 1-2 weeks.
• Major aphthous ulcers, which are large ulcers (more than 10mm) that take weeks or months to heal and do so with scarring.
• Herpetiform ulcers, which are multiple pinpoint ulcers that heal within a month. These are most commonly on the tongue.

Recurrent minor aphthous ulcers usually begin as a round yellowish elevated spot surrounded by a red halo. This then breaks down into an ulcer, which is covered with a loosely attached white or greyish membrane. Surrounding tissue is healthy and unaffected. Sometimes these ulcers can be painful, particularly if they are irritated by movement or from eating certain types of food.

People may experience a single ulcer or multiple ulcers. Multiple ulcers tend to be widely distributed throughout a person's mouth.

What is the treatment for aphthous ulcers?

There is no cure for aphthous ulcers. The main goal of treatment is to lessen the pain and discomfort they cause and promote healing of the ulcers. Most recurrent minor aphthous ulcers heal within 1-2 weeks without any treatment.

General measures

• Protective pastes that form a barrier over the ulcer so that exposure to irritating substances is reduced.
• Superficial tissue cauterization using silver nitrate stick
• Local anaesthetics benzocaine and lignocaine (lidocaine) to reduce pain
• Medicated toothpaste without sodium laureth sulfate
• Antibacterial mouthwashes to reduce secondary infection.
• Avoidance of foods that trigger or exacerbate the ulcers.
• Dietary supplements of vitamins or minerals, if diet is deficient.
• Reduction in stress

Prescribed medicines

Topical prescription medicines include:

• Tetracycline suspension as mouthwash
• Topical corticosteroids as lotions, creams or paste, often triamcinolone in dental paste
• Calcineurin inhibitors: topical pimecrolimus or tacrolimus.
• Colchicine

In very severe cases, particularly if there are systemic symptoms, anti-inflammatory oral medications may be considered (off-label use):

• Dapsone
• Systemic steroids
• Immunosuppressive agents such as azathioprine, methotrexate, ciclosporin
• Tumour necrosis factor (TNF) antagonists (adalimumab, etanercept, infliximab)
• Thalidomide.