While the oral ulcers are identical, a diagnosis of simple aphthous stomatitis is made when there are no other systemic features, whereas Behcet's requires other criteria like genital ulcers or uveitis.
Mucositis from chemotherapy is distinguished by a clear history of drug administration preceding the ulcers.
This is identified by the recurrent appearance of ulcers in the exact same location each time a specific drug is taken, a pattern not typical for Behcet's.
Recurrent herpes is distinguished by its preceding vesicular stage and location on keratinized mucosa, whereas Behcet's ulcers are non-vesicular and on non-keratinized mucosa.
Erosive lichen planus is differentiated by the presence of surrounding white, lacy (reticular) striations.
This autoimmune disease causes larger, more persistent, and scarring erosions, a more severe presentation than the recurrent, self-healing ulcers of Behcet's.
The presence of a low neutrophil count on a complete blood count is the defining feature that separates neutropenic ulcers from those of Behcet's.
Pemphigus vulgaris typically begins with extensive, fragile oral erosions that are more widespread and persistent than the discrete, punched-out ulcers of Behcet's.
This is an acute, severe reaction with widespread hemorrhagic crusting of the lips and sloughing, a far more dramatic event than the recurrent ulcerations of Behcet's.
Syphilitic ulcers are typically painless (chancre) or present as mucous patches, which are painless greyish plaques, unlike the painful ulcers of Behcet's.
