The Immunology of Contact Dermatitis

Contact dermatitis can be induced by a variety of small antigens. After binding of such antigens to a skin protein, they form a hapten-protein complex which can be incorporated into Langerhans cells or which can develop intracellularly. These complexes or their fragments can be presented via major histocompatibility complex (MHC) II by professional antigen-presenting cells or via MHC I by any cell present in the skin. The following activation of cytotoxic CD8+ T cells induces death of the presenting cell, including Langerhans cells or keratinocytes, which leads to an enormous release of immunoactive and chemoattractant cytokines and chemokines, initiating a strong inflammation.