Patch Testing Tools of the Trade: Techniques for Marking and Identifying Patch Application Sites

Epicutaneous patch testing is the diagnostic tool used to confirm the diagnosis of allergic contact dermatitis. Per standardized protocols, chemicals are applied to the skin and removed at 24Y48 hours. The sites aremarked at the time of removal to allow for easy identification of the sites later. Application sites are then evaluated at later time intervals (between 72 and 120 hours) for signs of inflammation (e.g., redness, induration). This article discusses the techniques for marking those patch tests to secure identification of the patch sites.