Aphthous stomatitis

Last updated: June 28, 2022

Summarytoggle arrow icon

Aphthous stomatitis (also known as canker sores) is characterized by frequent recurrent mouth ulcers. The cause of these painful, mostly benign sores is unknown, but they commonly occur after minimal trauma (e.g., biting the tongue). There are several types of aphthae, all of which can only be treated symptomatically.

Epidemiologytoggle arrow icon

  • Very frequent

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Clinical featurestoggle arrow icon

  • Painful mucosal ulcers in nonkeratinized areas of the mouth and throat
  • Efflorescence: round to oval, crater-like appearance on yellowish-grey base and erythematous margins
  • No systemic symptoms
  • Recurrence is common

Subtypes and variantstoggle arrow icon

  • Minor aphthous ulcers
    • Size: 5–10 mm
    • Heal within 1–2 weeks without scarring
    • Occur in 80% of affected patients
  • Major aphthous ulcers
    • Size: bigger (20–30 mm) and deeper than minor aphthous ulcers
    • Prolonged healing over several weeks with scarring
  • Herpetiform ulcers
    • Size: small (1–3 mm diameter)
    • Tendency to cluster
  • Bednar aphthae

Differential diagnosestoggle arrow icon

See “Differential diagnosis” in “Acute tonsillitis.”

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Prognosistoggle arrow icon

  • Benign, often recurrent
  • If ulcers persist for longer than 6 weeks, tests should be performed to rule out the possibility of malignancy.

Referencestoggle arrow icon

  1. Eichenfield LF, Frieden IJ, Zaenglein A, Mathes E. Neonatal and Infant Dermatology E-Book. Elsevier Health Sciences ; 2014

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 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer