[Allergic reactions to local anaesthetics]

Area of Science:

• Anesthesiology
• Clinical Immunology
• Dermatology

Background:

• Local anaesthetics (LA) are widely used in medical procedures.
• True allergy to LA is uncommon, affecting approximately 1% of patients with suspected reactions.
• Many suspected LA allergies are misdiagnosed, stemming from vasovagal responses, toxic effects, or reactions to additives.

Purpose of the Study:

• To investigate the diagnostic approach for patients with suspected local anaesthetic allergy.
• To differentiate true LA allergy from other adverse reactions.
• To establish strategies for identifying safe alternative treatments for patients with confirmed LA allergy.

Main Methods:

• Review of patient referrals for suspected LA allergy.
• Diagnostic workup including allergy testing (type I and type IV hypersensitivity reactions).
• Differential diagnosis to exclude non-allergic adverse events.

Main Results:

• A small percentage (approx. 1%) of suspected LA allergy cases are confirmed upon investigation.
• Non-allergic reactions, including vasovagal syncope and additive allergies, are common causes of suspected LA hypersensitivity.
• Appropriate diagnostic methods are essential for accurate diagnosis.

Conclusions:

• Thorough investigation is necessary to confirm or rule out local anaesthetic allergy.
• Identifying true allergy allows for the selection of safe alternative anaesthetic options.
• Distinguishing between immediate (type I) and delayed (type IV) hypersensitivity reactions guides diagnostic and management strategies.