Drug allergy
The diagnosis of a drug allergy is largely based on history and so any details/history are valuable. Please note that an adrenaline autoinjector is not required for a suspected drug allergy.
Drug Allergy: Diagnosis, management and referrals
Further information can be found here:
Drug Allergy: Diagnosis and Management (leedsth.nhs.uk)Notably, challenge tests are associated with their own inherent risks and some patients are not suitable for investigations. Commonly investigated drugs include penicillin, other anti-microbials, contrasts media and local anaesthetics.
Penicillin allergy
Due to a high volume of referrals, we only accept patients for penicillin allergy investigations if they meet NICE criteria:
- Penicillin is needed for a treatment for a disease or condition that can only be treated by a beta‑lactam antibiotic
- The patient is likely to need beta‑lactam antibiotics frequently in the future (for example, people with recurrent bacterial infections or immune deficiency) or
- The patient is allergic to penicillin, and cannot tolerate or is allergic to another antibiotic.
NSAID allergy
NSAIDs are well recognised as a cause for urticaria and angioedema, severe asthma exacerbations and occasionally anaphylactoid reactions. These reactions can occur even if the patient has tolerated NSAIDs in the past.
NSAIDs are well recognised as a cause for urticaria and angioedema, severe asthma exacerbations and occasionally anaphylactoid reactions. These reactions can occur even if the patient has tolerated NSAIDs in the past.
Patients with such reactions should avoid all NSAIDs and be vigilant to avoid over-the-counter preparations e.g. cold or flu remedies should be checked). They can have alternative analgesia such as Paracetamol or Codeine. Allergy testing is not likely to be of benefit since skin prick tests are not well validated for this class of drugs.
As per NICE guidance Recommendations for people who have had a mild allergic reaction (i.e. no features of anaphylaxis, no asthma exacerbations, but had mild angioedema and urticaria) to a non-selective NSAID but need an anti inflammatory:
- Discuss the benefits and risks of selective cyclooxygenase 2 (COX 2) inhibitors (including the low risk of drug allergy)
- Consider introducing a selective COX 2 inhibitor at the lowest starting dose with only a single dose on the first day.
Do not offer a selective COX 2 inhibitor to people in a non-specialist setting if they have had a severe reaction, such as anaphylaxis, severe angioedema or an asthmatic reaction, to a non-selective NSAID. Consider referring individuals who’ve had a severe reaction to NSAIDs and would benefit from access to a COX 2 inhibitor (e.g. has active inflammatory arthritis).
Anaesthetic drug allergy
The anaesthetic drug allergy clinic offers investigation of patients who may have had perioperative anaphylaxis.
Urgent referral criteria (consider a phone call discussion when making these referrals)
- Patient needs a drug for treatment of a current infection and there are no other options e.g. Benzathine penicillin for Treponema pallidum infection.
- Local anaesthetic allergy where clarity regarding allergy status is required before a procedure e.g. dental work
- Suspected contrast allergy which is preventing urgent imaging
Routine Referral
- Penicillin drug allergy referrals which meet NICE criteria
- Multiple antibiotic allergy which is limiting treatment options
- Other drug allergies where investigation would help ongoing care e.g. paracetamol
- severe reaction to and would benefit from access to a COX 2 inhibitor (e.g. has active inflammatory arthritis)
Not to refer
- Side effects to drugs
- Patient is very clear that they would not want to be re-exposed to the drug again