Copper hypersensitivity: dermatologic aspects.

Reports of immune reactions of both the immediate and delayed types due to cutaneous or systemic exposure to copper have been reviewed, in the endeavor to draw a comprehensive profile of the immunogenic potential of that metal and its compounds. The metal's immunotoxic potential is also briefly reviewed. In principle, as noted for other transition metals, the electropositive copper ion is potentially immunogenic due to its ability to diffuse through biological membranes to form complexes in contact with tissue protein. Based on predictive guinea pig test and the local lymph node assay (LLNA), copper has a low sensitization potential. Reports of immune reactions to copper include immunologic contact urticaria (ICU), allergic contact dermatitis (ACD), systemic allergic reactions (SAR) and contact stomatitis (STO), but considering the widespread use of copper IUDs and the importance of copper in coinage, items of personal adornment and industry, unambiguous reports of sensitization to the metal are extremely rare, and even fewer are the cases, which appear clinically relevant. Reports of immune reactions to copper mainly describe systemic exposure from intrauterine devices and prosthetic materials in dentistry, implicitly excluding induction of the hypersensitivity from contact with the skin as a risk factor. We provide a diagnostic algorithm that might clarify the frequency of copper hypersensitivity.