Angular cheilitis, part 1: local etiologies.

Angular cheilitis (AC) is a common condition characterized by erythema, moist maceration, ulceration, and crusting at the corners of the mouth. This article focuses on the common local factors that act alone and in combination to produce AC. These factors are categorized as irritant, allergic, and infectious causes. Identifying the underlying etiology of AC is a critical step in developing an effective treatment plan for this condition.