Frimley Guidelines

Anaphylaxis
Follow-up management of anaphylaxis in Adults

Key Points

  • This guideline provides information on the appropriate investigations, observation period, follow-up and safety netting for patients with anaphylactic reactions in the emergency department.

  • Please ensure that patients with suspected anaphylaxis are given emergency treatment with adrenaline first, prior to looking at this guide.

  • Advice is based on Resus Council guidance

Version:1
Date Issued:20/06/2024
Review Date:19/06/2027
Key words:Anaphylaxis

Emergency treatment for a suspected anaphylactic reaction

The routine use of corticosteroids to treat anaphylaxis is not advised.

Blood test

Take timed blood samples for mast cell tryptase testing as soon as possible after emergency treatment, ideally within 1-2 hours (but no later than 4 hours) from the onset of symptoms.

Inform the person that a blood sample may be required at follow-up with the specialist allergy service to measure baseline mast cell tryptase.

Assessment

Document the acute clinical features of the reaction

  • Rapidly developing, life threatening problems involving the airway (pharyngeal or laryngeal oedema) and/or

  • Breathing (bronchospasm with tachypnoea) and/or

  • Circulation (hypotension and/or tachycardia)

  • And, in most cases, associated skin and mucosal changes.

Record the time of onset of the reaction.

Record the circumstances immediately before the onset of symptoms.

Observation

Note: Consider giving steroids after initial resuscitation for refractory reactions or ongoing asthma/shock. Non-sedating oral antihistamines in preference to chlorphenamine may be given after initial stabilisation.

Fast track 2 hours

  • Good response (within 5-10 minutes) to a single dose of adrenaline given within 30 minutes of onset of reaction and

  • Complete resolution of symptoms and

  • The patient already has unused adrenaline auto-injectors and has been trained how to use them and

  • There is adequate supervision following discharge

6 hours

  • 2 doses of IM adrenaline needed to treat reaction or

  • Previous biphasic reaction

12 hours

  • Severe reaction requiring >2 doses of adrenaline

  • Patient has severe asthma or reaction involving severe respiratory compromise

  • Possibility of continuing absorption of allergen, e.g., slow release medicines

  • Patient presents late at night or may not be able to respond to any deterioration

  • Patients in areas where access to emergency care is difficult

Referral

Refer to specialist allergy service on Epic (Outpatient service option when you click Discharge).

Adrenaline Injector

Offer people (or, as appropriate, their parent and/or carer) an appropriate adrenaline injector as an interim measure before the specialist allergy appointment.

Patient information and support

Before discharge, offer the following:

  • A demonstration of the correct use of the adrenaline injector

  • Advice about how to avoid the suspected trigger (if known)

  • Information about the need for referral and the referral process

Give the patient the leaflet “Emergency treatment of anaphylactic reactions”.