ABSTRACT
Allergic contact dermatitis is one of the most frequent skin diseases. It can be caused by an almost countless number of substances and theoretically there is no compound in our environment incapable of acting as a sensitizer. However, substantial differences in the frequency of allergic contact dermatitis to these compounds do exist. Some of them become immunogenic only as an extremely rare exception, whereas others are a very common cause of hypersensitivity. Chromium has six valence states but only two of them, namely tri- and hexavalent salts, are sufficiently stable to be able to form covalent bonds with proteins. This protein-binding capacity is the general precondition of immunogenic activity of hapten shown by Landsteiner in 1935. From an immunological point of view, contact sensitivity is defined as an immunological reaction mediated by a particular type of lymphocytes without a noteworthy involvement of antibodies.
