There is controversy about the role of contact allergy in the pathogenesis of oral lichen planus (OLP) and the burning mouth syndrome (BMS). Patients with OLP or BMS might wish to pursue allergy testing in hopes of identifying the cause of their disease. Although patch testing in these conditions might provide useful information, one risks discovering allergens of uncertain relevance. We asked 2 experts in the field to discuss their approaches to evaluation and management of OLP and BMS, with an emphasis on the role of patch testing.