High risk of anaphylaxis to penicillin or severe non-IgE mediated reaction:

  • pruritic rash, urticaria (hives), immediate flushing, hypotension, angioedema, respiratory distress, or anaphylaxis
  • recurrent reactions, reactions to multiple B-lactams, or positive penicillin allergy test
  • severe delayed-onset cutaneous or systemic reactions such as eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome, Stevens-Johnson syndrome, or toxic epidermal necrolysis.