UMEM Educational Pearls


A 23 year-old male presents with the rash below. He originally presented to his primary care doctor for a sore throat and was given a prescription for a medication; this rash subsequently broke out. What's the diagnosis and which medication did he receive?


Rash secondary to Epstein-Barr pharyngitis treated with amoxicillin

  • Morbilliform rash occuring in up to 95% of patients given amoxicillin for EBV pharyngitis; the rash typically spreads to the trunk 
  • Other types of beta-lactams, cephalosporins, and macrolides may also cause this rash 
  • The exact mechanism is unknown but it is non-allergic; researchers have demonstrated that patients may receive amoxicilin after the rash resolves without adverse events.  
  • The rash spontaneously resolves in 1-2 weeks


Luzuriaga, K., Sullivan, J. Infectious Mononucleosis. N Engl J Med 2010; 362:1993-2000

Follow me on Twitter (@criticalcarenow) or Google+ (+criticalcarenow)