Immediate Reactions: Clinical Features and Management

Type of ReactionTiming of ReactionSymptoms of ReactionPossible Laboratories in Acute SettingDifferential DiagnosisCommonly Involved AntibioticsTestingManagement
Non–IgE-mediated reaction, mast cell activation (anaphylactoid, pseudoallergic)Immediate or during infusionUrticariaElevated mast cell tryptaseIgE-mediated reactionQuinolonesSerum total tryptase levealPretreatment
Can occur on first course of drugFlushingAnaphylaxisVancomycin (Red man syndrome)Serum histaminebSlow infusion speed (with Red man syndrome)
Angioedema (occasionally)Antihistamines
HypotensionDesensitize in some cases
Mild fever
Muscle pain in severe instances
IgE-mediated, anaphylactic-producing, immediate reaction1–6 h after administration of the drugAngioedemaElevated mast cell tryptaseNon–IgE-mediated mast cell activationβ-lactams (ie, aminopenicillins)Acute testing as aboveAvoid drugs and/or cross-reacting drugs
UrticariaFood allergyRarely non-β-lactams (macrolides)Allergy referral testing and possible testsDesensitization
RhinitisVenom allergySkin prick testing
ConjunctivitisIdiopathic urticaria and anaphylaxisSerum-specific IgE
HypotensionDrug provocation testing
Laryngeal edema
Gastrointestinal symptoms
Cardiovascular shock and hypotension
  • a Obtain serum total tryptase 15 minutes to 3 hours after reaction.

  • b Obtain 2-15 minutes after reaction.