Aphthous Stomatitis

Recurrent aphthous stomatitis (RAS), also known as "canker sores," is an oral ulcerative condition. Although a variety of host and environmental factors have been implicated, including trauma, nutritional deficiencies, and autoimmunity, the precise etiology remains unknown.

Three Clinical Forms

  1. Minor (< 7mm in diameter), most common
    • Appears as rounded, well-demarcated, single or multiple ulcers that usually heal in 10–14 days without scarring
  2. Major(>7 mm in diameter)
    • Usually take longer than 14 days to heal and may result in scarring
  3. Herpetiform


  • Recurring, painful, solitary, or multiple ulcers
  • Typically covered by a white to yellow pseudomembrane surrounded by an erythematous halo
  • Usually involves nonkeratinizing mucosa (e.g., labial mucosa, buccal mucosa, and ventral tongue)

Canker Sores

Joanna Douglass, BDS, DDS
Joanna Douglass, BDS, DDS
Joanna Douglass, BDS, DDS

Preventive Measures & Treatment

  •  Most mild aphthae require no treatment.
  • Application of Orabase, with or without topical steriods can be used for symptomatic relief.
  • Topical treatment with corticosteroids, such as fluocinonide gel or dexamethasone elixir, can promote healing and lessen severity.
  • Steroid injection of ulcers or systemic therapy with thalidomide, colchicine, pentoxifylline, or azathioprine may be necessary in severe cases of major aphthae.
  • Avoiding trigger foods or sodium lauryl sulfate in toothpaste can help reduce recurrences.
  • Celiac disease should be considered in patients with recurrent aphthous ulcers or stomatitis.


Neville BW, Damm DD, Allen CM, Bouqout JE. Recurrent aphthous stomatitis (recurrent aphthous ulcerations; canker sores). In: Oral & Maxillofacial Pathology. Philadelphia: W.B. Saunders Company; 2002. p. 285-90.

Eisenberg E. Diagnosis and treatment of recurrent apthous stomatitis. Oral Maxillofacial Surgery Clinics of North America 2003;15:111-22.

Chahine L, Sempson N, Wagoner C. The effect of sodium lauryl sulfate on recurrent aphthous ulcers: a clinical study. Compend Contin Educ Dent. 1997 Dec;18(12):1238-40.

Liu C, Zhou Z, Liu G, et al. Efficacy & Safety of dexamethasone ointment on RAU. Am J. Med. 2012; 125(3): 292-301.