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Drug allergy

About

What is covered

This pathway covers the diagnosis and management of drug allergy in adults, children and young people.
All drugs have the potential to cause side effects, also known as 'adverse drug reactions', but not all of these are allergic in nature. Other reactions are idiosyncratic, pseudo-allergic or caused by drug intolerance. The British Society for Allergy and Clinical Immunology (BSACI) defines drug allergy as an adverse drug reaction with an established immunological mechanism. The mechanism at presentation may not be apparent from the clinical history and it cannot always be established whether a drug reaction is allergic or non-allergic without investigation. Therefore, this pathway has defined drug allergy as any reaction caused by a drug with clinical features compatible with an immunological mechanism.
All recommendations apply to adults, children and young people.

Safeguarding children

Remember that child maltreatment:
  • is common
  • can present anywhere, such as emergency departments and primary care or on home visits.
Be aware of or suspect abuse as a contributory factor to or cause of the symptoms or signs of drug allergy in children. Abuse may also coexist with drug allergy. See the NICE pathway on when to suspect child maltreatment for clinical features that may be associated with maltreatment.
This section has been agreed with the Royal College of Paediatrics and Child Health.

Updates

Updates to this pathway

29 July 2015 Drug allergy (NICE quality standard 97) added.

Person-centred care

People have the right to be involved in discussions and make informed decisions about their care, as described in your care.
Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

Your responsibility

Guidelines

The recommendations in this guideline represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, professionals and practitioners are expected to take this guideline fully into account, alongside the individual needs, preferences and values of their patients or the people using their service. It is not mandatory to apply the recommendations, and the guideline does not override the responsibility to make decisions appropriate to the circumstances of the individual, in consultation with them and their families and carers or guardian.
Local commissioners and providers of healthcare have a responsibility to enable the guideline to be applied when individual professionals and people using services wish to use it. They should do so in the context of local and national priorities for funding and developing services, and in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities. Nothing in this guideline should be interpreted in a way that would be inconsistent with complying with those duties.
Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.

Technology appraisals

The recommendations in this interactive flowchart represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, health professionals are expected to take these recommendations fully into account, alongside the individual needs, preferences and values of their patients. The application of the recommendations in this interactive flowchart is at the discretion of health professionals and their individual patients and do not override the responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or their carer or guardian.
Commissioners and/or providers have a responsibility to provide the funding required to enable the recommendations to be applied when individual health professionals and their patients wish to use it, in accordance with the NHS Constitution. They should do so in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities.
Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.

Medical technologies guidance, diagnostics guidance and interventional procedures guidance

The recommendations in this interactive flowchart represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, healthcare professionals are expected to take these recommendations fully into account. However, the interactive flowchart does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer.
Commissioners and/or providers have a responsibility to implement the recommendations, in their local context, in light of their duties to have due regard to the need to eliminate unlawful discrimination, advance equality of opportunity, and foster good relations. Nothing in this interactive flowchart should be interpreted in a way that would be inconsistent with compliance with those duties.
Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.

Short Text

Everything NICE has said on diagnosing and managing drug allergy in an interactive flowchart

What is covered

This pathway covers the diagnosis and management of drug allergy in adults, children and young people.
All drugs have the potential to cause side effects, also known as 'adverse drug reactions', but not all of these are allergic in nature. Other reactions are idiosyncratic, pseudo-allergic or caused by drug intolerance. The British Society for Allergy and Clinical Immunology (BSACI) defines drug allergy as an adverse drug reaction with an established immunological mechanism. The mechanism at presentation may not be apparent from the clinical history and it cannot always be established whether a drug reaction is allergic or non-allergic without investigation. Therefore, this pathway has defined drug allergy as any reaction caused by a drug with clinical features compatible with an immunological mechanism.
All recommendations apply to adults, children and young people.

Safeguarding children

Remember that child maltreatment:
  • is common
  • can present anywhere, such as emergency departments and primary care or on home visits.
Be aware of or suspect abuse as a contributory factor to or cause of the symptoms or signs of drug allergy in children. Abuse may also coexist with drug allergy. See the NICE pathway on when to suspect child maltreatment for clinical features that may be associated with maltreatment.
This section has been agreed with the Royal College of Paediatrics and Child Health.

Updates

Updates to this pathway

29 July 2015 Drug allergy (NICE quality standard 97) added.

Sources

NICE guidance and other sources used to create this interactive flowchart.
Drug allergy: diagnosis and management (2014) NICE guideline CG183
Drug allergy (2015) NICE quality standard 97

Quality standards

Quality statements

Documentation using the structured assessment guide

This quality statement is taken from the drug allergy quality standard. The quality standard defines clinical best practice in drug allergy and should be read in full.

Quality statement

People with suspected drug allergy have their drug reaction documented using the structured assessment guide.

Rationale

After a person has a suspected allergic reaction to a drug, it is important that full and accurate information is recorded so that prescribing errors and adverse drug reactions can be avoided in the future. A healthcare professional can achieve this by following the structured assessment guide when recording the drug reaction and its severity. The guide is also important for educating patients about the signs, patterns and timings of allergic reactions. This should prevent morbidity and improve health outcomes.

Quality measures

Structure
Evidence of local arrangements to ensure that people with suspected drug allergy have their drug reaction documented using the structured assessment guide.
Data source: Local data collection.
Process
Proportion of people with suspected drug allergy who have their drug reaction documented using the structured assessment guide.
Numerator – the number in the denominator who have their drug reaction documented using the structured assessment guide.
Denominator – the number of people with suspected drug allergy.
Data source: Local data collection.
Outcome
a) Medication errors (inappropriate prescribing or administration of drugs).
Data source: Local data collection.
b) Number of repeat allergic drug reactions (including patient-reported episodes).
Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals, and commissioners

Service providers (GPs, A&E departments and secondary care services) ensure that people with suspected drug allergy have their drug reaction documented using the structured assessment guide.
Healthcare professionals use the structured assessment guide to document drug reactions of people with suspected drug allergy.
Commissioners (NHS England area teams and clinical commissioning groups) commission services in which people with suspected drug allergy have their drug reaction documented using the structured assessment guide.

What the quality statement means for patients, service users and carers

People with suspected drug allergy should be examined by their GP or, for severe reactions, by A&E staff, who should also ask questions about the symptoms. They should record details of the reaction using a standard approach. They should ask how soon the symptoms started after taking the drug or how many doses were taken, and whether the person has had a similar reaction to that drug or type of drug before. If the doctor thinks that a person might have a drug allergy they should discuss what this means with them (and their family members or carers as appropriate). They should also give them some written information.

Source guidance

  • Drug allergy (2014) NICE guideline CG183, recommendations 1.1.1 (key priority for implementation) and 1.2.3 (key priority for implementation).

Definitions of terms used in this quality statement

Structured assessment guide
The structured assessment guide (boxes 1–3) sets out the signs, allergic patterns and timing of onset of allergic reactions. Healthcare professionals should use boxes 1–3 as an assessment guide when deciding whether symptoms may be caused by a drug allergy.
Box 1 Immediate, rapidly evolving reactions
Anaphylaxis – a severe multi-system reaction characterised by:
  • erythema, urticaria or angioedema and
  • hypotension and/or bronchospasm
Onset usually less than 1 hour after drug exposure (previous exposure not always confirmed)
Urticaria or angioedema without systemic features
Exacerbation of asthma (for example, with non-steroidal anti-inflammatory drugs [NSAIDs])
Box 2 Non-immediate reactions without systemic involvement
Widespread red macules or papules (exanthema-like)
Onset usually 6–10 days after first drug exposure or within 3 days of second exposure
Fixed drug eruption (localised inflamed skin)
Box 3 Non-immediate reactions with systemic involvement
Drug 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
Onset 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
Onset 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
Onset usually 3–5 days after first drug exposure
Common disorders caused, rarely, by drug allergy:
  • eczema
  • hepatitis
  • nephritis
  • photosensitivity
  • vasculitis
Time of onset variable
[Drug allergy (2014) NICE guideline CG183, recommendation 1.1.1 (key priority for implementation)]

Advice about carrying personal structured drug information

This quality statement is taken from the drug allergy quality standard. The quality standard defines clinical best practice in drug allergy and should be read in full.

Quality statement

People with a new diagnosis of drug allergy are advised to carry structured information about their drug reaction at all times.

Rationale

Carrying structured information about their drug reaction at all times can minimise a person’s fear of having another reaction, enhance their communication with healthcare professionals and enable the person to better manage their drug allergy.

Quality measures

Structure
Evidence of local arrangements to ensure that people with a new diagnosis of drug allergy are advised to carry structured information about their drug reaction at all times.
Data source: Local data collection.
Process
Proportion of people with a new diagnosis of drug allergy who are advised to carry structured information about their drug reaction at all times.
Numerator – the number in the denominator who are advised to carry structured information about their drug reaction at all times.
Denominator – the number of people with a new diagnosis of drug allergy.
Data source: Local data collection.
Outcome
Self-management of drug allergy.
Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals, and commissioners

Service providers (primary and secondary care services) ensure that healthcare professionals advise people with a new diagnosis of drug allergy to carry structured information about their drug reaction at all times.
Healthcare professionals advise people with a new diagnosis of drug allergy to carry structured information about their drug reaction at all times.
Commissioners (NHS England area teams and clinical commissioning groups) commission services that advise people with a new diagnosis of drug allergy to carry structured information about their drug reaction at all times.

What the quality statement means for patients, service users and carers

People who have just been told they have a drug allergy are advised to keep the information they have been given about the allergy with them at all times.

Source guidance

  • Drug allergy (2014) NICE guideline CG183, recommendations 1.2.3 (key priority for implementation) and 1.3.4.

Definition of terms used in this quality statement

Structured information about a drug reaction
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)
  • 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.
If the person is unable to carry this information themselves (for example, neonates or those with additional needs), it may need to be given to a carer or family member instead, but confidentiality and safeguarding must be observed.
[Adapted from Drug allergy (2014) NICE guideline CG183, recommendation 1.2.3 (key priority for implementation)]

Equality and diversity considerations

All written information and advice should be accessible to people with additional needs such as physical, sensory or learning disabilities, and to people who do not speak or read English. People receiving information about drug allergy should have access to an interpreter or advocate if needed.

Referral to specialist drug allergy services

This quality statement is taken from the drug allergy quality standard. The quality standard defines clinical best practice in drug allergy and should be read in full.

Quality statement

People 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.

Rationale

It is important to ensure appropriate referral to specialist drug allergy services so that all people with drug allergy receive the care they need. Expert clinical opinion suggests that some people who are currently referred do not need specialist services whereas others need specialist referral but this is not offered.

Quality measures

Structure
Evidence of local arrangements to ensure that people 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.
Data source: Local data collection.
Process
a) Proportion of people with a suspected or confirmed anaphylactic reaction to a drug who are referred to a specialist drug allergy service.
Numerator – the number in the denominator who are referred to a specialist drug allergy service.
Denominator – the number of people with a suspected or confirmed anaphylactic reaction to a drug.
Data source: Local data collection.
b) Proportion of people with a severe non-immediate cutaneous reaction to a drug who are referred to a specialist drug allergy service.
Numerator – the number in the denominator who are referred to a specialist drug allergy service.
Denominator – the number of people with a severe non-immediate cutaneous reaction to a drug.
Data source: Local data collection.
c) Proportion of people with a reaction to a general anaesthetic who are referred to a specialist drug allergy service.
Numerator – the number in the denominator who are referred to a specialist drug allergy service.
Denominator – the number of people with a reaction to a general anaesthetic.
Data source: Local data collection.
Outcome
a) Mortality.
Data source: Local data collection.
b) Number of repeat allergic drug reactions.
Data source: Local data collection.
c) Length of hospital stay.
Data source: Local data collection.
d) Inappropriate avoidance of drugs.
Data source: Local data collection.
e) Further anaesthetics without problems.
Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals, and commissioners

Service providers (GP, A&E departments, dentists and secondary care services) ensure that people 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.
Healthcare professionals refer people with a suspected or confirmed anaphylactic reaction, or severe non-immediate cutaneous reaction to a drug, or reaction to a general anaesthetic to a specialist drug allergy service.
Commissioners (NHS England area teams and clinical commissioning groups) commission local specialist drug allergy services for people with suspected or confirmed anaphylactic reactions, or severe non-immediate cutaneous reactions to a drug, or reactions to general anaesthetics.

What the quality statement means for patients, service users and carers

People are referred to a specialist drug allergy service for advice if they have a severe ‘shock-like’ reaction straight after taking a drug, or if they have a severe skin reaction that develops later, or if they have a reaction to a general anaesthetic.

Source guidance

  • Drug allergy (2014) NICE guideline CG183, recommendations 1.4.2, 1.4.8 (key priority for implementation), 1.4.10 and 1.4.11 (key priority for implementation).
  • Anaphylaxis (2011) NICE guideline CG134, recommendation 1.1.9.

Recording drug allergy status in electronic medical records

This quality statement is taken from the drug allergy quality standard. The quality standard defines clinical best practice in drug allergy and should be read in full.

Quality statement

People with drug allergy have their status documented in their electronic medical record using the recommended coding framework.

Rationale

At present, the coding is not used consistently in electronic documentation systems to differentiate between a side effect and an allergic reaction. Consistent and comprehensive recording of drug allergy status is important to ensure that all patients with confirmed or suspected drug allergy have a full and accurate record of this in their electronic medical record. Accurate recording of drug allergy status will prevent the prescription and administration of drugs inducing allergic reactions and will improve patient safety.

Quality measures

Structure
Evidence of local arrangements to ensure that people with drug allergy have their status documented in their electronic medical record using the recommended coding framework.
Data source: Local data collection.
Process
Proportion of electronic medical records with a drug allergy status documented using the recommended coding framework.
Numerator – the number in the denominator with a drug allergy status documented using the recommended coding framework.
Denominator – the number of electronic medical records.
Data source: Local data collection.
Outcome
a) Mortality.
Data source: Local data collection.
b) Repeat allergic drug reactions.
Data source: Local data collection.
c) Length of hospital stay.
Data source: Local data collection.
d) Inappropriate avoidance of drugs.
Data source: Local data collection.
e) Anaphylaxis.
Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals, and commissioners

Service providers (primary and secondary care services) ensure that healthcare professionals document a person’s drug allergy status in their electronic medical record using the recommended coding framework.
Healthcare professionals document a person’s drug allergy status in their electronic medical record using the recommended coding framework.
Commissioners (NHS England area teams and clinical commissioning groups) commission services in which healthcare professionals document a person’s drug allergy status in their electronic medical record using the recommended coding framework.

What the quality statement means for patients, service users and carers

People have a note in their electronic medical record of whether or not they have a drug allergy. This should be noted as ‘drug allergy’, ‘none known’ or ‘unable to ascertain’ (doctors aren’t sure whether a reaction is due to drug allergy or not). If doctors aren’t sure they should investigate further.

Source guidance

  • Drug allergy (2014) NICE guideline CG183, recommendation 1.2.1.

Definitions of terms used in this quality statement

Coding framework for drug allergy status
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).
[Drug allergy (2014) NICE guideline CG183 recommendation 1.2.1]

Updating information on drug allergy status

This quality statement is taken from the drug allergy quality standard. The quality standard defines clinical best practice in drug allergy and should be read in full.

Quality statement

People 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.

Rationale

Updating information on drug allergy status and sharing this information among services is important for improving patient safety and reducing the costs associated with treating allergic reactions. Improved communication between primary and secondary healthcare providers will also allow safe prescription of alternative drugs and reduce inappropriate drug avoidance. Full details of the drug and allergic reaction are important if the same drug is needed again and also improve diagnostic accuracy if the patient needs specialist investigation of the allergy.

Quality measures

Structure
Evidence of local arrangements to ensure that people 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.
Data source: Local data collection.
Process
a) Proportion of GP referral letters for people with a new diagnosis of drug allergy with updated drug allergy status.
Numerator – the number in the denominator with updated drug allergy status.
Denominator – the number of GP referral letters for people with a new diagnosis of drug allergy.
Data source: Local data collection.
b) Proportion of hospital discharge letters for people with a new diagnosis of drug allergy with updated drug allergy status.
Numerator – the number in the denominator with updated drug allergy status.
Denominator – the number of hospital discharge letters for people with a new diagnosis of drug allergy.
Data source: Local data collection.
Outcome
a) Mortality.
Data source: Local data collection.
b) Repeat allergic drug reactions.
Data source: Local data collection.
c) Length of hospital stay.
Data source: Local data collection.
d) Inappropriate avoidance of drugs.
Data source: Local data collection.
e) Anaphylaxis.
Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals, and commissioners

Service providers (primary and secondary care services) ensure that healthcare professionals update drug allergy status in all GP referral and hospital discharge letters for people with a new diagnosis of drug allergy.
Healthcare professionals update drug allergy status in all GP referral and hospital discharge letters for people with a new diagnosis of drug allergy.
Commissioners (NHS England area teams and clinical commissioning groups) commission services in which healthcare professionals update information on drug allergy status in all GP referral and hospital discharge letters for people with a new diagnosis of drug allergy.

What the quality statement means for patients, service users and carers

People have any new information about drug allergy added to their records. The information is also included by their GP in all letters referring them to a hospital or clinic, and in all letters sent to their GP when they leave hospital.

Source guidance

  • Drug allergy (2014) NICE guideline CG183, recommendation 1.2.7.

Prescription information on drug avoidance: developmental

This quality statement is taken from the drug allergy quality standard. The quality standard defines clinical best practice in drug allergy and should be read in full.
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.

Developmental quality statement

People with a drug allergy have information included on their prescriptions about which drugs or drug classes to avoid.

Rationale

Recording information on drug avoidance on a prescription is important for patient safety. Expert opinion suggests that only some hospitals have prescription forms which include drug allergy status.

Quality measures

Structure
Evidence of local arrangements to ensure that prescriptions have drug allergy information included about which drugs or drug classes to avoid.
Data source: Local data collection.
Process
a) Proportion of paper prescriptions issued in any healthcare setting which have drug allergy information included about which drugs or drug classes to avoid.
Numerator – the number in the denominator which have drug allergy information about which drugs or drug classes to avoid.
Denominator – the number of paper prescriptions issued in any healthcare setting.
Data source: Local data collection.
b) Proportion of electronic prescriptions issued in any healthcare setting which have drug allergy information included about which drugs or drug classes to avoid.
Numerator – the number in the denominator which have drug allergy information about which drugs or drug classes to avoid.
Denominator – the number of electronic prescriptions issued in any healthcare setting.
Data source: Local data collection.
Outcome
a) Mortality.
Data source: Local data collection.
b) Repeat allergic drug reactions.
Data source: Local data collection.
c) Inappropriate avoidance of drugs.
Data source: Local data collection.

What the quality statement means for service providers, healthcare professionals, and commissioners

Service providers (secondary care) ensure that people with a drug allergy have information included on their prescriptions about which drugs or drug classes to avoid.
Healthcare professionals issue prescriptions which have drug allergy information included about which drugs or drug classes to avoid.
Commissioners (NHS England area teams and clinical commissioning groups) commission services in which people with a drug allergy have information included on their prescriptions about which drugs or drug classes to avoid.

What the quality statement means for patients, service users and carers

People with a drug allergy are given prescriptions which include information on any drugs or types of drug that they should avoid.

Source guidance

  • Drug allergy (2014) NICE guideline CG183, recommendation 1.2.4.

Effective interventions library

Effective interventions library

Successful effective interventions library details

Implementation

NICE has produced resources to help implement its guidance on:

Information for the public

NICE produces information for the public that summarises, in plain English, the recommendations that NICE makes to healthcare and other professionals.
NICE has written information for the public explaining its guidance on each of the following topics.

Pathway information

Person-centred care

People have the right to be involved in discussions and make informed decisions about their care, as described in your care.
Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

Your responsibility

Guidelines

The recommendations in this guideline represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, professionals and practitioners are expected to take this guideline fully into account, alongside the individual needs, preferences and values of their patients or the people using their service. It is not mandatory to apply the recommendations, and the guideline does not override the responsibility to make decisions appropriate to the circumstances of the individual, in consultation with them and their families and carers or guardian.
Local commissioners and providers of healthcare have a responsibility to enable the guideline to be applied when individual professionals and people using services wish to use it. They should do so in the context of local and national priorities for funding and developing services, and in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities. Nothing in this guideline should be interpreted in a way that would be inconsistent with complying with those duties.
Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.

Technology appraisals

The recommendations in this interactive flowchart represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, health professionals are expected to take these recommendations fully into account, alongside the individual needs, preferences and values of their patients. The application of the recommendations in this interactive flowchart is at the discretion of health professionals and their individual patients and do not override the responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or their carer or guardian.
Commissioners and/or providers have a responsibility to provide the funding required to enable the recommendations to be applied when individual health professionals and their patients wish to use it, in accordance with the NHS Constitution. They should do so in light of their duties to have due regard to the need to eliminate unlawful discrimination, to advance equality of opportunity and to reduce health inequalities.
Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.

Medical technologies guidance, diagnostics guidance and interventional procedures guidance

The recommendations in this interactive flowchart represent the view of NICE, arrived at after careful consideration of the evidence available. When exercising their judgement, healthcare professionals are expected to take these recommendations fully into account. However, the interactive flowchart does not override the individual responsibility of healthcare professionals to make decisions appropriate to the circumstances of the individual patient, in consultation with the patient and/or guardian or carer.
Commissioners and/or providers have a responsibility to implement the recommendations, in their local context, in light of their duties to have due regard to the need to eliminate unlawful discrimination, advance equality of opportunity, and foster good relations. Nothing in this interactive flowchart should be interpreted in a way that would be inconsistent with compliance with those duties.
Commissioners and providers have a responsibility to promote an environmentally sustainable health and care system and should assess and reduce the environmental impact of implementing NICE recommendations wherever possible.

Supporting information

After specialist drug allergy investigations, allergy specialists should document:
  • the diagnosis, drug name and whether the person had an allergic or non-allergic reaction
  • the investigations used to confirm or exclude the diagnosis
  • drugs or drug classes to avoid in future.

Signs and allergic patterns of suspected drug allergy with timing of onset

Note that these boxes describe common and important presenting features of drug allergy but other presentations are also recognised.

Immediate, rapidly evolving reactions

Anaphylaxis – a severe multi-system reaction characterised by:
  • erythema, urticaria or angioedema and
  • hypotension and/or bronchospasm
Onset usually less than 1 hour after drug exposure (previous exposure not always confirmed)
Urticaria or angioedema without systemic features
Exacerbation of asthma (for example, with NSAIDs)

Non-immediate reactions without systemic involvement

Widespread red macules or papules (exanthem-like)
Onset 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 involvement

DRESS or drug hypersensitivity syndrome characterised by:
  • widespread red macules, papules or erythroderma
  • fever
  • lymphadenopathy
  • liver dysfunction
  • eosinophilia
Onset 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
Onset usually 7–14 days after first drug exposure or within 3 days of second exposure
Acute generalised exanthematous pustulosis characterised by:
  • widespread pustules
  • fever
  • neutrophilia
Onset usually 3–5 days after first drug exposure
Common disorders caused, rarely, by drug allergy:
  • eczema
  • hepatitis
  • nephritis
  • photosensitivity
  • vasculitis
Time of onset variable

Glossary

cyclooxygenase 2
drug reaction with eosinophilia and systemic symptoms
immunoglobulin E
non-steroidal anti-inflammatory drug

Paths in this pathway

Pathway created: September 2014 Last updated: November 2016

© NICE 2017

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