Anaphylaxis

Scope

Anaphylaxis is an acute severe systemic reaction which is most often allergic (but can be non-allergic, previously called anaphylactoid). It is commonly associated with urticaria and angioedema and occurs within minutes (typically less than 1 hour) of a trigger (e.g. food/ drug/ sting). Anaphylaxis is characterised by one or more of:

  1. Airway – tongue/throat swelling, difficulty talking/hoarse voice
  2. Breathing – shortness of breath, wheeze, persistent cough
  3. Circulation – persistent dizziness or collapse, loss of consciousness
  4. Neurological – sense of impending doom, visual changes

NICE guidance is that patients with a history of anaphylaxis should be referred to a specialist allergy clinic, and according to the specialist services national definition set 17 for allergy, "patients with anaphylaxis must be seen in a specialist allergy centre and not managed in the community".

For guidelines describing the management of urticaria and angioedema in the absence of systemic features see guidance for spontaneous urticaria and angioedema

Investigations

Stings: check specific IgE to bee and wasp venom and mast cell tryptase.

Foods: check specific IgE to specific suspect foods 4 weeks after index reaction. There is no need to investigate foods which have been tolerated since the reaction as these are not the trigger.

Drugs: Ensure potential drug allergies are explained to the patient, and documented in the medical records with appropriate details.

If there is a clear history consider identification jewellery.

Assessment and Management

Signs and Symptoms

  1. Anaphylaxis should be treated according to Resus Council guidelines, Acute measurement of mast cell tryptase (immediately and 2 hours after the onset of symptoms) should be performed.
  2. Identify any potential triggers (e.g. foods, drugs, stings, exercise) in the 4 hours before the reaction.
  3. Advise patients to avoid potential triggers identified in the history pending further investigations. If a suspected trigger has been tolerated since the reaction it is excluded as a cause
  4. Prescribe self-injectable adrenaline (0.3mg x 2) with appropriate training to patients with:
    1. Anaphylaxis (see definition above) or a less severe allergic reaction in patients with asthma; And
    2. A potentially unavoidable suspected cause.

All patients must have appropriate training in use of self-injectable adrenaline: How to use your EpiPen

Drug reactions are not an indication for self-injectable adrenaline, as drugs can usually be avoided unless there is altered consciousness.

Referral

Referral Criteria

Include details of index reaction with copy of appropriate correspondence (e.g.ED discharge summary) and suspected triggers.

Consider referral of patients with anaphylaxis, particularly for patients with

  1. Drug reactions in whom
    1. There is diagnostic uncertainty or multiple drugs were involved (especially where the reaction is systemic or involves blistering or desquamation)
    2. The suspected drug is considered essential for the patient's ongoing management, and where alternatives clinically not suitable. Please document reasons for needing treatment with the drug.
  2. Venom allergy
  3. No obvious trigger
  4. Co-factors (e.g. asthma, cardiovascular disease).

Patients with an obvious food trigger and no cofactors need not be referred

Referral Instructions

Refer to Peninsula Immunology and Allergy Service

Refer via DRSS for NEW Devon CCG patients

Refer using e-Referral Service

  • Specialty: Allergy
  • Clinic type: Allergy
  • Service: DRSS-Eastern-Allergy-Devon CCG- 15N

Referral forms

DRSS Referral forms

 

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