Anaphylactic reactions to local anesthetics

Area of Science:

• Anesthesiology
• Allergology
• Clinical Immunology

Background:

• Local anesthetics (LA) frequently cause adverse reactions mimicking anaphylaxis.
• The exact pathomechanism of immediate hypersensitivity to LA remains largely unknown, often termed 'pseudo-allergic' reactions.
• Non-anesthetic components like preservatives or latex may trigger reactions.

Purpose of the Study:

• To investigate the diagnostic approaches for patients reporting adverse reactions to local anesthetics.
• To differentiate between true allergic reactions and other causes of LA-related symptoms.
• To evaluate the efficacy of a 'reverse placebo provocation' strategy.

Main Methods:

• Comprehensive allergy history taking.
• Skin prick tests and intradermal tests with LA solutions (considering potential false positives).
• Placebo-controlled subcutaneous provocation testing and 'reverse placebo provocation' for psychosomatic evaluation.

Main Results:

• Immunologically mediated reactions to LA are rare, with few positive skin tests.
• False-positive intradermal tests can occur with undiluted LA.
• Reverse placebo provocation can help desensitize patients and confirm LA tolerance, reducing anxiety.

Conclusions:

• Accurate diagnosis of LA hypersensitivity requires a multi-step approach, including careful testing.
• Distinguishing true allergy from other reactions is crucial for patient management.
• The reverse placebo provocation method offers a valuable tool to confirm LA tolerance and alleviate patient concerns.