Vaccines · Pharmacology

What is the underlying cause of an Arthus reaction, which can occasionally manifest as severe localized pain and swelling at a booster injection site?

  1. The rapid destruction of red blood cells by cytotoxic T cells
  2. A Type III hypersensitivity reaction from local antigen-antibody immune complexes
  3. A Type I IgE-mediated anaphylactic emergency that shuts down the airways
  4. The colonization of the muscle tissue by contaminating ambient bacteria
Show answer and explanation

Correct answer: A Type III hypersensitivity reaction from local antigen-antibody immune complexes

An Arthus reaction is a localized Type III hypersensitivity reaction that can occur when an individual with high levels of pre-existing circulating IgG antibodies receives a booster dose. The injected antigen quickly complexes with the concentrated local antibodies, depositing immune complexes in the vessel walls, activating complement pathways, and triggering localized vascular inflammation.

Difficulty: Medium Question 24 of 25

Practice all 25 Vaccines questions

Keep practicing

More Vaccines questions