ABSTRACT
Immunologic contact urticaria is mediated through IgE antibodies that identify molecules entering the body through skin and perceive them as foreign. IgE antibody-mediated reactions are most commonly seen in atopics. The molecule causing reactions has to penetrate epidermal layers, including the stratum corneum as well as basement membrane, before it attaches to IgE bound on mast cell surfaces in the dermis. The responsible molecules must have suffi cient size and contain amino acid sequences to be able to bind to IgE. Therefore, the most usual molecules causing ICU are proteins or large-molecule-size polypeptides. Smaller peptides or chemicals have to bind to a carrier protein to be able to trigger immune response. After the responsible molecule binds to the IgE on mast cell, the cell releases infl ammatory mediators, including histamine, cytokines, and chemokines, which cause itch, infl ammation, and swelling in the skin. The swelling is seen as edema, the principal feature of urticaria [1].
