Serum sickness

Last updated: June 13, 2023

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Summarytoggle arrow icon

Serum sickness is a type III hypersensitivity reaction that usually develops as a complication of antitoxin or antivenom administration, but can also occur after antibiotic administration and hepatitis B infection. Symptoms typically occur 1–3 weeks after exposure to the offending agent and include fever, rash, and arthralgia. It is diagnosed clinically and treatment consists primarily of removing the offending agent.

Definitiontoggle arrow icon

Serum sickness is a classic example of a type III hypersensitivity reaction, which usually develops as a complication of antitoxin or antivenom administration.

Etiologytoggle arrow icon

Pathophysiologytoggle arrow icon

Exposure to an antigen (e.g., antivenom, drug) → formation of antibodies deposition of antibody-antigen complexes in tissue → activation of the complement cascade → tissue damage and systemic inflammation

Clinical featurestoggle arrow icon

Symptoms appear 1–3 weeks following initial exposure (because antibodies take several days to form) and typically resolve within a few weeks after discontinuation of the offending agent.

Diagnosticstoggle arrow icon

Differential diagnosestoggle arrow icon

See also “Hypersensitivity reactions.”

Serum sickness-like reaction

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Prognosis is excellent once the offending drug is stopped or the causative infection has resolved.

Referencestoggle arrow icon

  1. $Contributor Disclosures - Serum sickness. None of the individuals in control of the content for this article reported relevant financial relationships with ineligible companies. For details, please review our full conflict of interest (COI) policy:.
  2. Solensky R, Khan DA et al. Drug Allergy: An Updated Practice Parameter. Ann Allergy Asthma Immunol. 2010; 105 (4): p.259-273.e78.doi: 10.1016/j.anai.2010.08.002 . | Open in Read by QxMD

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