Metal allergy: Mercury

Mercury allergy is a clinically relevant condition because it underlies both oral and/or systemic disease caused by a type IV hypersensitivity. Humans are exposed to mercury from mercury-containing dental amalgam filling, fish consumption, and vaccines. There are no safe levels of mercury exposure in humans, and hypersensitivity to mercury, the patient’s clinical condition, and the severity of disease are not related to the dose. Skin patch testing and lymphocyte transformation testing (LTT) are useful to confirm or rule out the presence of mercury hypersensitivity. Avoidance of elemental and inorganic mercury (mercury-based dental amalgam) and organic mercury (fish and seafood) is the first-line treatment for allergy to mercury.