A patient who uses a corticosteroid inhaler presents with a wipeable white lesion on the palate. What is the most likely diagnosis?

Inhaled corticosteroids (ICS) cause local immunosuppression in the oral cavity, predisposing patients to oral candidiasis (pseudomembranous type, or thrush). The deposited corticosteroid suppresses the local immune response, allowing overgrowth of Candida albicans. The classic presentation is a wipeable white plaque (pseudomembrane) on the palate, tongue, or buccal mucosa, which when removed leaves an erythematous, bleeding base. This distinguishes it from leukoplakia (cannot be wiped off). Prevention: patients should rinse with water and spit immediately after using the inhaler, and use a spacer device. Treatment: topical nystatin or clotrimazole troches.