Clinical Manifestations
Prodrome (24-48 hours before ulcer): burning or tingling sensation at the site where the ulcer will develop — reported by many RAS patients.
Active ulcer: round or oval, well-defined ulcer with a yellow-grey pseudomembranous center and a distinct erythematous (red) halo. Exquisitely painful — pain disproportionate to lesion size.
Location: non-keratinized mucosa — buccal mucosa, labial mucosa, lateral tongue, floor of mouth, soft palate. Notably ABSENT from hard palate, attached gingiva, and dorsal tongue (these sites are involved in primary herpetic gingivostomatitis and herpes simplex recurrences).
Constitutional symptoms are absent in minor RAS. Fever, malaise, and lymphadenopathy if present suggest herpetic infection or systemic disease association.
Recurrence pattern is characteristic: ulcers heal, free period, then new crop — endlessly recurring, hence 'recurrent aphthous stomatitis.'