Drs Taha Nasser and Shuaib Nasser (pictured) pose the question ‘What is a GP’s role if a patient presents with a possible drug allergy?’

nasser shuaib

Read this article to learn more about:

  • using the structured assessment guide to help distinguish allergic from non-allergic adverse reactions
  • what information should be given to patients with drug allergy
  • when to refer patients with allergic-type reactions to specialist services.

Key points

Audit points

CP commissioning messages

Monitoring of inpatient admissions and complications has shown that drug reactions are on the rise. Hospital Episode Statistics collected between 1996 and 2000 show that each year drug allergies and adverse drug reactions account for around 62,000 hospital admissions in England. In the period between 1998 and 2005, serious drug reactions rose 2.6 fold.1

Furthermore, analysis of patient safety incidents reported to the National Reporting and Learning System between 2005 and 2013 identified 18,079 incidents involving drug allergy, including 6 deaths, 19 'severe harms', 4980 'other harms', and 13,071 'near-misses'.1 In most of these cases, a drug was prescribed, dispensed or administered to a patient who had a previously known allergy to that drug or drug class.1

These statistics indicate that significant improvements could be made across primary and secondary care to the current system of diagnosing, managing, and communicating about drug allergy. While medical schools usually ensure that students are taught about anaphylactic reactions to drugs, the finer details of hypersensitivity reactions can be lost. Adverse drug reactions are more nuanced than simply causing anaphylaxis and comprise a variety of true allergic responses caused by an established immunological mechanism2,3 as well as non-allergic responses (drug intolerance, rare idiosyncratic reactions, or pseudo-allergy), see Figure 1, below4

Figure 1: Flowchart showing allergic and non-allergic responses in adverse drug reactions
Flowchart showing allergic and non-allergic responses in adverse drug reactions

DHS=drug hypersensitivity syndrome; DRESS=drug rash eosinophillia and systemic symptoms

As a result of these subtleties, diagnosis can be challenging and patients are often misdiagnosed. Approximately 500,000 people every year are admitted to hospital with a label of drug allergy, most often to penicillin.5 In reality fewer than 10% of these people have true penicillin allergy.6 The result of such inaccuracy is unnecessary exposure to broad spectrum antibiotics (which contributes to antimicrobial resistance),1 avoidable morbidity and mortality7-11 and increased cost.12,13

The problem is compounded by inaccurate or incomplete documentation that does not record the severity of the reaction nor distinguish between true drug allergy and other adverse reactions.7,12,13 The NICE Quality Standard 97 on drug allergy, published in July 2015, outlines measures to help counter these problems and improve the future diagnosis and management of drug allergy.14 It forms the basis for the remainder of this article.

Principles of care described in Quality Standard 97

Any patient presenting with a suspected allergic response should be seen and dealt with as a matter of urgency. If still being given, the suspected drug should be stopped immediately and the patient assessed using an airway, breathing, circulation, disability, and exposure approach. Adrenaline can be life saving in cases of anaphylaxis. The full treatment algorithm, as produced by the Resuscitation Council UK, can be found in Figure 2, Below.15

Figure 2: Algorithm for the key steps in treating an anaphylactic reaction15
Algorithm for the key steps in treating an anaphylactic reaction

IV=intravenous; ECG=electrocardiogram; IM=intramuscular;
Resuscitation Council (UK). Emergency treatment of anaphylactic reactions. Guidleines for healthcare providers. Resus Council, 2008
Available at: www.resus.org.uk/_resources/assets/attachment/full/0/824.pdf
Reproduced with permission

With regards to longer term management, the NICE quality standard defines six statements that signpost the best care in cases of drug allergy (see Table 1, below). These encompass the diagnosis, management, documentation, and communication of drug allergy in an effort to create a benchmark of care that would improve outcomes dramatically while being realistic.14

Table 1: NICE quality standard for drug allergy—list of quality statements14
No.Quality statement
1People with suspected drug allergy have their drug reaction documented using the structured assessment guide.
2People with a new diagnosis of drug allergy are advised to carry structured information about their drug reaction at all times.
3People with a suspected or confirmed anaphylactic reaction, or severe non immediate cutaneous reaction to a drug, or reaction to a general anaesthetic are referred to a specialist drug allergy service.
4People with drug allergy have their status documented in their electronic medical record using the recommended coding framework.
5People with a new diagnosis of drug allergy who are being referred or discharged have their drug allergy status updated in all GP referral and hospital discharge letters.
6(developmental) People with a drug allergy have information included on their prescriptions about which drugs or drug classes to avoid.
Developmental quality statements set out an emerging area of service delivery or technology currently found in a minority of providers and indicating outstanding performance. They will need specific, significant changes to be put in place, such as redesign of services or new equipment.

NICE (2015) QS97. Drug allergy. Available at: www.nice.org.uk/guidance/qs97
Reproduced with permission

Documentation using the structured assessment guide—statement 1
The structured assessment guide (see Table 2, below) mentioned in the quality statements helps to distinguish among anaphylactic reactions, non-immediate cutaneous reactions, and non-allergic responses and should be used as a framework for history taking and examination in a patient with suspected drug allergy.11,14,16,17

Table 2: Structured assessment guide and when to refer14
Immediate, rapidly evolving reactionsAnaphylaxis—a severe multi-system reaction characterised by:
  • erythema, urticaria or angioedema and
  • hypotension and/or bronchospasm.
usually less than 1 hour after drug exposure (previous exposure not always confirmed)Document with details and refer accordingly (see Box 2, below)
Urticaria or angioedema without systemic features
Exacerbation of asthma (for example, with non-steroidal anti-inflammatory drugs [NSAIDs])
Non-immediate reactions without systemic involvementWidespread red macules or papules (exanthema-like)usually 6–10 days after first drug exposure or within 3 days of second exposure
Fixed drug eruption (localised inflamed skin)
Non-immediate reactions with systemic involvementDrug reaction with eosinophilia and systemic symptoms (DRESS) or drug hypersensitivity syndrome (DHS) characterised by:
  • widespread red macules, papules, or erythroderma
  • fever
  • lymphadenopathy
  • liver dysfunction
  • eosinophilia.
usually 2–6 weeks after first drug exposure or within 3 days of second exposure
Toxic epidermal necrolysis or Stevens–Johnson syndrome characterised by:
  • painful rash and fever (often early signs)
  • mucosal or cutaneous erosions
  • vesicles, blistering, or epidermal detachment
  • red purpuric macules or erythema multiforme.
usually 7–14 days after first drug exposure or within 3 days of second exposure
Acute generalised exanthematous pustulosis (AGEP) characterised by:
  • widespread pustules
  • fever
  • neutrophilia.
usually 3–5 days after first drug exposure
Common disorders caused, rarely, by drug allergy:
  • eczema
  • hepatitis
  • nephritis
  • photosensitivity
  • vasculitis.
variableDo not refer

In cases where the clinical signs and symptoms are ambiguous, the following factors should be considered: whether or not the patient took the drug around the time the reaction happened, whether the drug is known to cause that kind of reaction or if the patient has had similar symptoms when not taking the drug.16

Advice about carrying personal structured drug information—statement 2
The patient should be given a detailed, portable record of the reaction to keep on their person14 (see Box 1, Below). This should serve to prevent recurrence or unnecessary avoidance of drugs.18

Box 1: Structured information about a drug reaction14

When a person presents with a new diagnosis of drug allergy they are advised to carry structured information about their drug reaction that includes:

  • the generic and proprietary name of the drug or drugs suspected to have caused the reaction, including the strength and formulation
  • a description of the reaction (see structured assessment guide [table 2, above])
  • the indication for the drug being taken (or description of the illness if there is no clinical diagnosis)
  • the date and time of the reaction
  • the number of doses taken or number of days on the drug before onset of the reaction
  • the route of administration
  • which drugs or drug classes to avoid in future.

NICE (2015) QS97. Drug allergy. Available at: www.nice.org.uk/guidance/qs97
Reproduced with permission

Referral to specialist drug allergy services—statement 3
Patients who display truly allergic reactions of any kind or those reacting to general anaesthetics, as well as some patients who react to local anaesthetics, NSAIDs or beta-lactam antibiotics should be referred to specialist allergy services14 (see Table 2,14 above and Box 2,1 below).

Box 2: Referral of patients to a specialist drug allergy service1

Refer people to a specialist drug allergy service if:

  • they need treatment with an NSAID and have had a suspected allergic reaction to an NSAID with symptoms such as anaphylaxis, severe angioedema or an asthmatic reaction
  • allergy to beta-lactam antibiotics is suspected and if they—
    • need treatment for a disease or condition that can only be treated by a beta-lactam antibiotic or
    • are likely to need beta-lactam antibiotics frequently in the future (for example, people with recurrent bacterial infections or immune deficiency)
  • they need a procedure involving a local anaesthetic that they are unable to have because of suspected allergy to local anaesthetics
  • they have had anaphylaxis or another suspected allergic reaction during or immediately after general anaesthesia.

NSAID=non-steroidal anti-inflammatory drug

Adapted from NICE (2015) QS97. Drug allergy. Available at: www.nice.org.uk/guidance/qs97
Reproduced with permission

While history taking and examination aid the diagnosis and management of drug allergy, once the patient is stable a mast cell tryptase level can help inform a final diagnosis.16 A clotted sample should ideally be taken as soon after the reaction as feasible, and another a few hours later.19 The medical notes and pathology request forms should document how long after the reaction onset each sample was taken.16 The results of these tests should be sent with the referral to allergy services.

Recording drug allergy status in electronic medical records—statement 4
Once clearly categorised using the structured assessment guide (Table 2, above), drug reactions should be recorded in the electronic medical record using the recommended coding framework (see Box 3, below), which should clearly distinguish between allergic and non-allergic reactions.

Box 3: Coding framework for drug allergy status1,14

Use 1 from the following coding framework when documenting a person's drug allergy status in their medical records:

  • 'drug allergy'
  • 'none known'
  • 'unable to ascertain' (document it as soon as the information is available).

NICE (2015) QS97. Drug allergy. Available at: www.nice.org.uk/guidance/qs97
Reproduced with permission

Updating information on drug allergy status—statement 5
In addition to accurately coding the drug reaction into the patient’s electronic medical record and giving them a note to carry, healthcare professionals should ensure that the reaction is shown on all referral and discharge correspondence to and from hospital. Since some patients may not read or fully understand the information given to them, the names and classes of drugs that they should avoid should also be written on all prescriptions.14 This serves as important documentation, especially for pharmacy staff who may not always have access to referral or discharge letters. Computer systems that automatically update drug reactions with the desired level of detail into referral letters, discharge letters and prescriptions may be useful.

Prescription information on drug avoidance—statement 6
A 'drug allergy box' is generally available on prescriptions issued in secondary care; however, the FP10 prescription issued in primary care does not provide any information on which drugs and drug classes the patient should avoid. In an attempt to standardise best practice, and reduce this inequality, developmental quality statement 6 was included. In practice, implementation should not be difficult as most FP10 prescriptions are issued by computer and a list of drugs to avoid could easily be auto-populated. This would enhance patient safety by providing an additional opportunity for the dispensing pharmacist to check the prescription.

Barriers to implementation and how they might be overcome

In the limited time that primary care professionals have to see their patients, accurately documenting, coding and informing the patient as well as updating correspondence can be challenging. Those working in trusts that employ different computer systems between primary and secondary care facilities and where access to pathology results is not shared may also find it difficult to effect multiple actions for each patient with a relevant drug allergy.

Shared, common IT systems that naturally integrate coded drug reaction information into all relevant correspondence and prescriptions would help offset this problem. Such systems should have the sensitivity to distinguish between drug allergies and other adverse drug reactions and to understand when a user alert or prompt is necessary. This would thus sidestep many clinicians' habit of overriding reminders. Re-designing and standardising prescription forms and hospital drug charts to include structured allergy information as well as continuously auditing and training relevant healthcare professionals would also help improve implementation of the standards and patient safety.16

Auditing and improving allergy management in primary care

Given that most primary care services care for a large number of patients and that a significant number of these will either develop or have a label of drug allergy,20,21 any audit assessing drug allergy management includes a large data set. In order to prevent the audit process from becoming unrealistically time consuming, searching through computerised records with multiple search queries and cross matching the results may be a useful approach.

The obvious search queries include 'allergy', 'allergic reactions', 'anaphylaxis', 'reaction to general anaesthesia' or any of the other suspected drug allergies that should be referred to specialist allergy services. The NICE quality statements indicate other outcomes such as medication errors, adverse effects of polypharmacy (e.g. where multiple antibiotics are used instead of one to which the patient is erroneously considered allergic) and drug related mortality.14 Key points for audit can be found below.


Drug allergy poses a risk to patient safety with evidence of a lack of documentation, patient information, and continuing errors in prescribing and dispensing. It is likely that improvements in documentation, communication of drug allergy status between health service providers, and patient information will improve outcomes. Much of this will need to be carried out in primary care through changes in computer software. NICE QS97 sets a benchmark for care, requiring drug reactions to be correctly categorised and clinical details recorded using a structured proforma.14 In order to reduce prescribing errors this information should be provided to each affected individual and communicated on every referral letter and hospital discharge summary. Confirmation or exclusion of drug allergy is provided by specialist drug allergy services for certain patients. All prescriptions should clearly indicate the drugs or drug classes that need to be avoided.

Key points

  • Adverse drug reactions are on the increase
  • Inadequate diagnosis, documentation, and treatment increases morbidity and mortality
  • Not all drug reactions are allergic—use the structured assessment guide to help distinguish from non-allergic adverse reactions
  • Take blood for mast cell tryptase levels around the time of the reaction and a few hours later
  • Many allergy clinics can assess patients with drug allergy
  • Refer patients with anaphylactic or allergic-type reactions to specialist services and include mast cell tryptase results
  • Record the details of the drug reaction in the patient’s electronic care record using a structured proforma
  • Give the patient a verbal and written summary of the drug reaction and what to avoid in the future
  • Include drug reaction information on all referral and discharge correspondence
  • Include drug reaction information on all prescriptions.

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Audit points

Within the practice:

  • Documentation of drug reactions, was the structured assessment guide used?
  • Informing patients with a drug allergy diagnosis—is standardised information provided?
  • Is the diagnosis recorded with detail in the electronic record? Is it coded correctly?

With other services:

  • Do referral and discharge letters include drug allergy information?
  • Are all patients who need referral being referred?
  • Are inappropriate patients being referred?

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GP commissioning messages 

written by Dr David Jenner, NHS Alliance GMS contract/PBC Lead

  • The NICE quality standard requires accurate diagnosis, recording, and coding of potential drug allergy:
    • commissioners could work with primary care to ensure that this is done with the core clinical record, which with appropriate patient consent will increasingly be available to other providers through the ESCR
  • ‘Autoconsultations’, which are available in clinical software systems, can be used to prompt accurate recording and coding of potential drug allergy and ensure key information is captured and included in the ESCR:
    • this information can be printed out and given to the patient to carry with them; it can include other, similar drugs that should be avoided
  • Commissioners should ensure that all acute care providers have clear clinical pathways for the management of severe suspected drug allergy, with appropriate referral pathways for people who require specialist assessment
  • In cases of suspected anaphylaxis, blood should be taken immediately for mast cell tryptase and then again a few hours later to help identify genuine anaphylaxis.

ESCR=electronic summary care record

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