Is there a role of food additives in recurrent aphthous stomatitis? A prospective study with patch testing

Background Recurrent aphthous stomatitis ( RAS ) is a common disease of the oral mucosa with an unknown etiology. This study aimed to determine if food additives play a role in the etiology of RAS as well as to determine if patch testing can be used to detect which allergens cause RAS . Methods This prospective study included 24 patients with RAS and 22 healthy controls. All the participants underwent patch testing for 23 food additives. Results In total, 21 (87.5%) RAS patients and 3 (13.6%) controls had positive patch test reactions to ≥1 allergens; the difference in the patch test positivity rate between groups was significant ( P  < 0.05). The most common allergen that elicited positive patch test results in the patient group was cochineal red ( n  = 15 [62.5%]), followed by azorubine ( n  = 11 [45.8%]) and amaranth ( n  = 6 [25%]). Conclusions The present findings show that food additives might play a role in the etiology of RAS and that patch testing could be a method for determining the etiology of RAS .