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Aphthous stomatitis

Last updated: August 9, 2021

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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.

  • Very frequent

Epidemiological data refers to the US, unless otherwise specified.

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

  • 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

See “Differential diagnosis” in acute tonsillitis

The differential diagnoses listed here are not exhaustive.

  • Benign, often recurrent
  • If ulcers persist for longer than 6 weeks, test should be conducted to rule out the possibility of malignancy.
  1. Eichenfield LF, Frieden IJ, Zaenglein A, Mathes E. Neonatal and Infant Dermatology E-Book. Elsevier Health Sciences ; 2014