Unnecessarily labelling patients “allergic” to a drug can be harmful and deny them the best treatment, say the authors of a new paper published in the British Journal of Medicine.
The paper sets out a systematic approach to assessing a patient who reports a drug allergy is presented:
- Establish if the harm was caused by medication or something else, such as a consequence of the condition being treated.
- If it was an adverse drug reaction (ADR), did it fit the ‘serious’ criteria?
- Was it a true immunological allergy? Some life-threatening ADRs have a delayed onset, making them difficult to diagnose. Also, some treatments can provoke a non-immunological release of mediators that can lead to immune like symptoms.
- Was it a benign T-cell mediated rash?
- If this is the case, was it related to the dose?
The authors advise clinicians to ask patients, “have you ever had a bad experience with a medicine”, rather than asking specifically about drug allergy. They add that a detailed history and specialist tests can help optimise prescribing decisions.