FS02.1 The role of metallurgy in allergic contact dermatitis to metals

Abstract

The critical factor in determining if an alloy may induce metal sensitisation or elicit allergic contact dermatitis is the release rate of soluble metal ions of allergenic metals at the skin surface. Metals or alloys in direct and prolonged contact with body fluids may result in electrochemical reactions (commonly called corrosion) that release metal ions. Induction or elicitation of metal allergy results if a sufficient amount of metal ions are released and absorbed through the skin where they react with the human immune system. The virtual insolubility of most metals and alloys in aqueous media (including body fluids) limits the bioavailability of metal ions. Several factors influence the rate of corrosion: metal or alloy metallurgical structure, surface films, surface finish, geometry, process history, and composition; body fluid composition, amount, pH, electrolytic properties, dissolved oxygen and other gas content; and the service environment (e.g. temperature, flow rate, etc). A review of recently published studies on metal allergy from a metallurgical perspective provides information that helps explain why certain metals and alloys cause allergic reactions and others (e.g. most stainless steels) do not. This information is useful in predicting what alloys will cause allergic reactions under varying conditions. In order to predict allergic reactions and responses to metals and alloys, metallurgical aspects of ion release should be taken into account. This presentation will increase understanding and interpretation of results of clinical or other scientific studies (e.g. studies in vitro) of reactions and responses to metals and alloys by providing a metallurgical perspective.