A drug allergy is an allergic reaction to medication that occurs when the immune system is incorrectly activated by a drug. All drugs can cause allergic reactions that range from skin rashes/hives/itching, skin swellings, a runny nose, itchy watery eyes to shortness of breath/wheezing and dizziness. Drug anaphylaxis is a life-threatening reaction to a drug with reactions including:
- tightening of the airways and throat/difficulties breathing
- nausea, vomiting, diarrhoea; dizziness/lightheadedness with a drop in blood pressure
- loss of consciousness or even a cardiac arrest/death
The most common triggers include: penicillins (and other antibiotics), non-steroidal anti-inflammatory drugs (Aspirin, ibuprofen, naproxen), local anaesthetics (lignocaine) and general anaesthetics.
Initial treatment of a drug allergy requires discontinuation of the suspected drug and focus on relieving symptoms with antihistamines, corticosteroids and – in severe cases – adrenaline.
Drug allergy is diagnosed by an allergy specialist experienced in the management of various types of drug allergy. Diagnosis can include skin prick and intradermal tests with the relevant drugs; blood tests and a drug provocation (challenge) test where a small amount of the suspect drug is administered in a graded fashion under medical supervision.
