Hypersensitivity Reaction

The condition in which the immune system reacts in an extreme way to a substance in the body, including type 1 (IgE - immediately to minutes - anaphylaxis, asthma, hives, hay fever), type 2 (IgM, IgG - minutes to hours - hemolytic anemia, cytopenias, Goodpasture's syndrome), type 3 (IgG - 6 hours - serum sickness, arthus reaction, vasculitis), type 4 (sensitized lymphocytes - delayed 12 to 48 hours - cutaneous hypersensitivity reactious, graft rejection).