Author: Vanessa Ngan, Staff Writer, 2003. Updated by A/Prof Amanda Oakley, Chief Editor, January 2016.
An aphthous ulcer is an ulcer that forms on the mucous membranes. They are also called aphthae, aphthosis, aphthous stomatitis and canker sores.
An aphthous ulcer is typically a recurrent round or oval sore or ulcer inside the mouth on an area where the skin is not tightly bound to the underlying bone, such as on the inside of the lips and cheeks or underneath the tongue. Aphthous ulcers can also affect the genitalia in males and females.
Recurrent aphthous ulcers are mostly a minor nuisance, but they are associated with significant health problems in some people.
Anyone can get an aphthous ulcer; 20% of the population have one or more, at least occasionally. They usually first appear in childhood or adolescence, and more commonly affect females than males.
Interestingly, smoking may be protective against aphthae, even though smoking make many oral and skin conditions worse.
Non-sexually acquired genital ulceration (NSGU) refers to aphthous ulcer in genital sites. A genital aphthous ulcer is also called a Lipschutz ulcer.
NSGU is more likely than simple oral aphthosis to be associated with systemic illness, such as:
The exact reason why aphthous ulcer develops is not yet clearly defined. Approximately 40% of people who get aphthous ulcers have a family history of aphthous ulcer. Current thinking is that the immune system is disturbed by some external factor and reacts abnormally against a protein in mucosal tissue.
Factors that seem to trigger outbreaks of ulcers include:
Other causes of mouth ulcer should be considered, including:
Recurrent aphthous ulcer usually begins as a round yellowish elevated spot surrounded by a red halo. This then breaks down into a punched-out ulcer, which is covered with a loosely attached white, yellow or greyish membrane. Surrounding tissue is healthy and unaffected. The ulcer can be painful, particularly if irritated by movement or eating certain types of food such as citrus fruit.
People may experience a single ulcer or multiple ulcers. Multiple ulcers tend to be widely distributed throughout a person's mouth.
Aphthous ulcer is classified into three types.
Most people affected by occasional minor aphthous ulceration do not require tests. They are undertaken if there are recurrent attacks of multiple or severe oral ulcers, or complex aphthosis.
Blood tests may include:
There is no cure for aphthous ulcer. Most recurrent minor aphthous ulcers heal within 1–2 weeks without any treatment. The main goal of treatment is to lessen pain and discomfort, and promote healing.
Topical prescription medicines include:
In severe cases, particularly if there are systemic symptoms, anti-inflammatory oral medications may be considered (off-label use):
See the DermNet NZ bookstore.
© 2019 DermNet New Zealand Trust.
DermNet NZ does not provide an online consultation service. If you have any concerns with your skin or its treatment, see a dermatologist for advice.