Drug Allergy

Introduction

Adverse drug reactions can be immediate or delayed¹ and can be allergic or non-allergic. Clinical history and documentation of the reaction is paramount. Document all new reactions promptly and thoroughly to assist in future investigation.

 

Scope:                             Diagnosis and management of drug allergy in those over 16 years

Not in scope:                  Any other allergy

Anaphylaxis

Anaphylaxis or another suspected allergic reaction during or immediately after general anaesthesia. These referrals should be sent to the Anaesthetic Allergy Service inbox at:  plh-tr.PlymouthAnaestheticAllergyService@nhs.net

 

Red Flags

Arrange emergency hospital admission if the adverse drug reaction is serious or life threatening.

• Anaphylaxis
• Non immediate cutaneous reactions with systemic involvement
  • Steven Johnson Syndrome or Toxic Epidermal Necrolysis
  • Drug reaction with eosinophilia and systemic symptoms (DRESS) or drug hypersensitivity syndrome (DHS)
  • Acute generalised exanthematous pustulosis (AGEP)
  • Acute Skin Failure

*this list is not exhaustive

Further information on the assessment of drug reactions can be found here.

 

Management Optimisation

In the absence of red flag features requiring emergency management and referral, the management of a suspected drug reaction is as follows:

• The suspected drug should be stopped immediately
   
• Promptly document the reaction thoroughly, with at minimum
  • the drug name
  • the signs, symptoms and severity of the reaction
  • the date and time of onset of reaction after taking the drug
  • reason drug was given
• Explain the allergy to the patient and document in the medical records
  • if there is a clear history consider identification jewellery
  • advise patients to avoid drugs identified as likely causes of reaction
• Report to the Medicines and Healthcare products Regulatory Agency (MHRA), using the Yellow Card Scheme, all suspected adverse drug reactions (ADRs)² that fulfil their criteria.

 

Investigations prior to referral

No investigations in Primary Care are required prior to referral.

Specific IgE (RAST) testing to drugs should not be used in a non-specialist setting¹

 

 

Advice and Guidance

No advice and guidance service is available.

 

Referral instructions

There is a referral form available, which would help to minimise returned referrals. Only the relevant section needs to be completed. GPs have the right to refer via referral letter in the usual way.

All information regarding reactions, timing and implicated drugs should be included in the referral.

 

NICE guidance¹ on how to document the reaction in a structured approach:

1. the generic and proprietary name of the drug or drugs suspected, including the strength and formulation
2. a description of the reaction
3. the indication for the drug being taken
4. the route of administration
5. which drugs or drug classes to avoid in the future

 

Referral Criteria

Refer any patient over the age of 16 with one of the following drug related allergies:

1. Following acute treatment and recovery of a severe non-immediate cutaneous reaction (e.g. Steven-Johnson Syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms [DRESS]). Please include in the referral any preferred alternative classes of medication which could be considered to facilitate more directed investigations.
    
2. Non-immediate cutaneous reaction where that class of drug is considered essential to management.
    
3. NSAID reactions involving urticaria, angioedema, or an asthmatic reaction to a non-selective NSAID (E.g. ibuprofen, naproxen, diclofenac)
    
4. Beta lactam allergy when:
   a.    Beta lactams are considered essential for management
   b.    There is likely to be frequent need for beta-lactam antibiotics in the future (e.g. recurrent bacterial infections or immune deficiency)
   c.    There is suspected allergy to at least one other class of antibiotics in addition to beta lactams
    
5. Suspected local anaesthetic allergy where a procedure involving local anaesthetic is needed
    
6. There is diagnostic uncertainty, or multiple drugs were involved (especially where the reaction is systemic)

 

 

Supporting Information

For patients

MedicAlert | Medical ID | Jewellery & Services

Drug Allergy | Allergy UK | National Charity

 

For professionals

Recommendations | Drug allergy: diagnosis and management | Guidance | NICE

Eden Unit GP Information | University Hospitals Plymouth NHS Trust

Yellow Card | Making medicines and medical devices safer

Scenario: Adverse drug reactions | Management | Adverse drug reactions | CKS | NICE

 

References

1. Recommendations | Drug allergy: diagnosis and management | Guidance | NICE
2. Adverse drug reactions | Health topics A to Z | CKS | NICE

 

 

Review Date                            16 March 2025

Next Review Date                   16 March 2027

Speciality Lead GP                 Dr Kate Northridge

Contributors                            Dr Catherine Elliott, Specialist Doctor in Allergy, University Hospital Plymouth