Do beta blockers (beta-adrenergic blocking agents) need to be discontinued prior to allergy testing?

Beta Blocker Therapy Prior to Allergy Testing

Beta blockers do not need to be routinely discontinued prior to diagnostic allergy skin testing, though they represent a relative contraindication that requires clinical judgment based on individual risk assessment. 1

Key Clinical Distinction

The concern about beta blockers relates primarily to allergen immunotherapy (treatment), not diagnostic skin testing 1. The evidence and guidelines address these as separate clinical scenarios:

For Diagnostic Skin Testing

• Skin prick testing can be safely performed in patients on beta blockers with appropriate precautions and emergency preparedness 2
• A retrospective analysis of 191 patients taking beta blockers during skin testing showed zero adverse events, demonstrating relative safety of skin prick tests in this population 2
• Beta blockers do not interfere with the interpretation of skin test results (unlike antihistamines), as they do not suppress the histamine-mediated wheal and flare response 3

For Allergen Immunotherapy (Treatment)

• Beta blocker use is considered a relative contraindication to allergen immunotherapy, not an absolute contraindication 1
• The theoretical concern is that beta blockade may worsen anaphylaxis severity and make it more resistant to epinephrine treatment if a systemic reaction occurs during immunotherapy 1
• However, in patients who cannot safely discontinue beta blockers but require venom immunotherapy for moderate-to-severe sting-induced anaphylaxis, immunotherapy is still indicated because the risk of anaphylaxis from a sting exceeds the risk from immunotherapy 1

Clinical Decision Algorithm

For routine diagnostic skin testing:

• Proceed with testing while patient remains on beta blocker 2
• Ensure emergency equipment and medications are immediately available
• Consider patient's overall anaphylaxis risk (history of severe reactions, asthma severity) 4

For allergen immunotherapy:

• Attempt to substitute beta blocker with alternative medication when medically feasible 1
• If beta blocker cannot be discontinued due to compelling cardiovascular indications (severe coronary disease, ventricular arrhythmia), immunotherapy may still proceed with enhanced monitoring 1
• Document risk-benefit discussion with patient 1

Important Caveats

• Pregnancy and beta blocker therapy together represent additional contraindications for procedures with higher anaphylaxis risk 4
• The evidence shows no increased frequency or severity of anaphylactic reactions during immunotherapy in patients on beta blockers in controlled studies, though theoretical concerns persist 1
• Ophthalmic beta blocker drops (for glaucoma) carry the same considerations as oral beta blockers 5
• If anaphylaxis occurs in a patient on beta blockers, expect potentially severe, protracted reactions resistant to conventional epinephrine doses, requiring aggressive and prolonged support 5

Medications That DO Require Discontinuation

Unlike beta blockers, antihistamines must be discontinued before allergy skin testing 6:

• Second-generation H1-antihistamines: discontinue 3-7 days before testing 3
• Tricyclic antidepressants: significant interference, discontinue if clinically able 3
• H2-blockers: may cause some interference 3