Lorraine is 25 years old and presents with a 1 week history of 2 mouth ulcers which feel sore. She describes having tried several over the counter treatments for them with little pain relief. Past medical history is unremarkable and she cannot recall having mouth ulcers before. On examination, you observe a two 4mm round ulcers on her inner left cheek. You explain this is a minor aphthous ulcer and discuss this further.
Which one of the following statements about aphthous ulcers is least correct?
