Serum sickness

From WikEM
Jump to: navigation, search


Clinical Features

  • Primary occurs 6-21 days after exposure
    • 1-4 days after subsequent exposures to the same antigen
  • Fever
  • Arthralgia
  • Lymphadenopathy
  • Skin eruption (rash)

Differential Diagnosis


Algorithm for Polyarticular arthralgia


  • Clinical diagnosis in which labs may be suggestive but not required[1]
    • Careful investigation of new medications
    • List of serum sickness medications extensive
  • Mild leukopenia or leukocytosis
  • ESR elevation
  • Mild proteinuria
  • Mild hematuria
  • Mild serum creatinine elevation
  • Decreased C3, C4
  • Other labs to obtain:
    • CH50
    • LFTs
    • Urine electrolytes (Na, K, Cr, eosinophils)
    • ESR and CRP
    • HepB, HepC panel, HIV, RPR/VDRL



Admit for:

  • Significant comorbidities (advanced or very young age, immunocompromised)
  • Severe symptoms
  • Hemodynamic instability/hypotension
  • Unclear diagnosis


  • Symptoms usually last 1-2 weeks before spontaneously subsiding
  • Long-lasting sequelae generally do not occur
  • Fatalities are rare and usually are due to continued administration of the antigen


  1. Alissa HM et al. Serum Sickness Workup. Dec 14, 2015.