Aphthous Ulcers


Last updated: November 2023

Also known as: Apthae, recurrent aphthous stomatitis (RAS), recurrent oral aphthae, mikulicz ulcers, sutton’s ulcer, periadenitis mucosa necrotica recurrens (PMNR), canker sores, simple or complex aphthosis, non-sexually acquired genital ulceration (NSGU)

What are aphthous ulcers?

Aphthous ulcers are common ulcers of the oral mucosa, and present as a painful sore on oral or genital mucous membranes. They can be classified as simple, complex or non-sexually acquired genital ulceration (NSGU).

Who gets aphthous ulcers?

Aphthous ulcers are common. They affect between 5% and 25% of the Australian population, and are more common in adolescents and men. 1

Individuals living in high socioeconomic areas are more likely to develop aphthous ulcers.

What causes aphthous ulcers?

The exact cause of aphthous ulcers is unknown. Approximately 40% of individuals who get aphthous ulcers have a family history of aphthous ulcers. 2 A weakened immune may also play a role in the development of aphthous ulcers.

Some other factors that trigger an outbreak of aphthous ulcers may include:

  • Trauma
  • Vitamin deficiencies – such as iron, folate or vitamin B1, B2, B6 and B12 deficiencies
  • Hormonal fluctuations – such as menstruation and pregnancy
  • Toothpastes containing sodium lauryl sulphate
  • Smoking cessation
  • Psychological stress
  • Infections
  • Medication allergy – such as nicorandil
  • Food hypersensitivities
  • Genetic factors
  • HIV infection
  • Gluten sensitivity or Coeliac disease

What do aphthous ulcers look like?

Aphthous ulcers are often round, shallow and painful with a creamy-white or grey film and red halo. They occur predominantly in the skin inside the mouth but can also occur in the genital areas.

Individuals may experience a single or multiple ulcers.

Aphthous ulcers are classified into three categories:

  1. Simple aphthous ulcers: These are the most common type of aphthous ulcer and have three main types.
    • Minor aphthous ulcers, also known as Mikulicz ulcers, usually first appear in childhood or adolescence. The ulcers are usually shallow, less than 5 mm in size and heal within 1 to 2 weeks.
    • Major aphthous ulcers, also known as Sutton’s ulcers, usually appear in childhood or adolescence. The ulcers are usually 1 to 3 cm in size and take about 6 weeks to heal and leave a scar.
    • Herpetiform aphthous ulcers usually appear in young adults. There are usually multiple ulcers between 1 to 2 mm in size and are shallow and heal without leaving a scar.
  1. Complex aphthous ulcers: These usually occur when there are either more than three oral ulcers present or there are recurrent oral and genital lesions.
  2. Non-sexually acquired genital ulceration (NSGU): NSGU refers to complex aphthous ulcers in genital areas. It may be preceded by flu-like symptoms and is possibly linked with viral infections such as the Epstein-Barr virus (EBV).

How are aphthous ulcers diagnosed?

Aphthous ulcers are usually diagnosed clinically.

Complex aphthous ulcers may require blood tests including:

  • Blood count, iron, vitamin B12 and folate levels
  • Gluten antibody tests for coeliac disease
  • Faecal calprotectin test for Crohn’s disease

A biopsy is rarely required, but is necessary if the ulcer does not heal within 3 to 4 weeks. A swab of the ulcer is also essential to evaluate the presence of a viral, bacterial or candida infection.

How are aphthous ulcers treated?

Treatment options will vary depending on the individual and their needs.

Most recurrent minor aphthous ulcers heal without treatment in a couple of weeks. The aim of treatment is to:

  • relieve pain
  • ensure adequate nutrition
  • promote ulcer healing
  • prevent the ulcers from recurring.

Some general measures, include:

  • Applying protective pastes that form a barrier around the ulcer to help relieve pain.
  • Using antibacterial mouthwashes regularly to reduce secondary infection.
  • Avoiding toothpaste with sodium lauryl sulphate
  • Avoiding foods that trigger the ulcers Ensure a soft or liquid diet.
  • Reducing stress.
  • Treating underlying factors such as vitamin deficiencies.

Topical prescription medicines are rarely needed, but may include corticosteroids and analgesics.

In severe cases, oral medications may be used, such as:

  • Tetracycline
  • Dapsone
  • Colchicine
  • Immunosuppressive drugs such as azathioprine, methotrexate
  • Clofazimine
  • Ascorbic acid (vitamin C)
  • Pentoxifylline
  • Monteleukast
  • Thalidomide

Biologic agents such as adalimumab, etanercept and infliximab have also been reported to help as well as the oral phosphodiesterase-4 inhibitor apremilast in severe resistant cases. The use of laser, such as CO2 and Nd:YAG may also improve symptoms.

What is the likely outcome of aphthous ulcers?

In most individuals the condition resolves after several years.

  1. Barrons RW. Treatment strategies for recurrent oral aphthous ulcers. Am J Health Syst Pharm. 2001 Jan 1;58(1):41-50; quiz 51-3. PMID: 11194135.
  2. Scully C, Porter S. Oral mucosal disease: recurrent aphthous stomatitis. Br J Oral Maxillofac Surg. 2008 Apr;46(3):198-206. doi: 10.1016/j.bjoms.2007.07.201. Epub 2007 Sep 11. PMID: 17850936.
Dr Sara TrittonNovember 2023
Dr Sara TrittonJuly 2022


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