What are the types of immunologically mediated drug eruptions?

Updated: Oct 14, 2020
  • Author: Jonathan E Blume, MD; Chief Editor: Dirk M Elston, MD  more...
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Coombs and Gell proposed four types of immunologically mediated reactions, as follows:

  • Type I is immunoglobulin E (IgE)–dependent reactions, which result in urticaria, angioedema, and anaphylaxis (see the image below).

    Urticaria. Urticaria.
  • Type II is cytotoxic reactions, which result in hemolysis and purpura (see the image below).

    Oral ulcerations in a patient receiving cytotoxic Oral ulcerations in a patient receiving cytotoxic therapy.
  • Type III is immune complex reactions, which result in vasculitis, serum sickness, and urticaria.

  • Type IV is delayed-type reactions with cell-mediated hypersensitivity, which result in contact dermatitis, exanthematous reactions, and photoallergic reactions.

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