Dental personnel are exposed to a high number of sensitizing chemicals such as acrylics, metals, anesthetics, fragrances, and antimicrobials. Although these chemicals usually cause allergic contact dermatitis, they also may cause immediate contact reactions. Usually the diagnostics involve patch testing, but prick testing needs to be performed to confirm immediate allergy. This article reviews the important causes and diagnostics of skin allergy in dental personnel. Special attention is given to the acrylates and methacrylates.