Aphthous ulcers are distinguished by occurring on non-keratinized mucosa (cheeks, tongue) and not being preceded by vesicles, whereas recurrent herpes favors keratinized mucosa (hard palate, gums).
The ulcers in Behcet's are part of a systemic syndrome with genital ulcers and uveitis, and they are not preceded by vesicles.
This is widespread, painful ulceration directly following a cycle of chemotherapy, a different context than a recurrent viral outbreak.
Oral EM involves widespread erosions and hemorrhagic crusting of the lips, often triggered by herpes, but it is a more severe, reactive process than a simple herpes outbreak.
This is a recurrent ulcer in the exact same spot triggered by a drug.
The oral ulcers in HFMD are accompanied by characteristic oval vesicles on the palms and soles.
This coxsackievirus infection is distinguished by causing ulcers specifically on the posterior pharynx and soft palate.
This is a chronic autoimmune disease causing large, scarring erosions, a different process than the acute, self-limited vesicles of herpes.
Pemphigus vulgaris typically begins with extensive, flaccid bullae and erosions in the mouth that are more persistent and widespread than recurrent herpes.
SJS is an acute, severe mucocutaneous reaction with widespread, hemorrhagic crusting of the lips and extensive mucosal sloughing.
