Introduction
It is essential to distinguish a true allergy from a non-allergic reaction (side effect, vasovagal episode) so that any future medical procedure can be carried out safely.
Symptoms
- Acute urticaria, itching
- Angio-oedema (lips, eyelids, tongue)
- Widespread redness, feeling of warmth
- Bronchospasm, difficulty breathing
- Low blood pressure, feeling faint
- In severe cases: perioperative anaphylaxis
Causes
- True allergic reactions (immunological mechanism, rare)
- Non-allergic reactions (toxic, vasovagal, anxiety, overdose)
- Local anaesthetics (e.g. lidocaine, articaine)
- General anaesthetics (induction agents)
- Neuromuscular blocking agents (curare-like drugs)
- Perioperative antibiotics
- Antiseptics (chlorhexidine)
- Latex
- Preservatives (sulphites, parabens)
Diagnosis
- Detailed history (circumstances, timeline, drugs administered)
- Review of the anaesthetic record
- Allergy tests performed some weeks after the reaction: Specific skin tests Patch tests if a delayed reaction is suspected Targeted blood tests Controlled challenge tests (selected cases)
- Specific skin tests
- Patch tests if a delayed reaction is suspected
- Targeted blood tests
- Controlled challenge tests (selected cases)
Treatments
- Strict avoidance of the identified substance
- Identification of safe alternative anaesthetics
- Antihistamines and corticosteroids depending on the initial reaction
- Adrenaline auto-injector prescribed if there is a history of severe reaction
- An official written allergy report
- prevention of recurrence
- safe alternative anaesthetics
- official written allergy report
Management
Confirm or rule out a true allergy
Distinguish allergy from a non-allergic reaction
Make dental, surgical and aesthetic procedures safe
Give clear instructions to anaesthetists and other doctors