[Mercury--is it a respiratory tract allergen?]

Mercury is a well-known allergen in dermato-allergology, often manifesting as delayed type hypersensitivity contact eczema. Immediate hypersensitivity reactions (urticaria, anaphylactic shock) have also been described for this allergen, most frequently seen in patients with the delayed type contact eczema. To our knowledge this allergen has not been implicated in production of respiratory symptoms. We describe a patient who had aggravation of asthma by mercury contained in dental amalgam. When the dental amalgam was removed there was a great improvement in his asthma. This observation suggests that mercury in the form of dental amalgam may also be an allergen of the respiratory tract, which should not be surprising, bearing in mind the work that shows the existence of mercury vapours from dental amalgam.