MICA · FIRST-LINE LEARNING NOTES
Understand, prioritise and organise follow-up
Anaphylaxis is a clinical emergency: recognise airway, breathing or circulatory compromise and promptly give first-line treatment through a trained care pathway.
Recognise a serious systemic reaction
Consider anaphylaxis when laryngeal symptoms, stridor, bronchospasm, faintness or shock develop rapidly, particularly after a compatible exposure. Urticaria or angioedema supports the diagnosis but its absence does not exclude it. Conversely, isolated urticaria without airway, breathing or circulatory compromise is insufficient to define anaphylaxis. Act on progression and context rather than waiting for a complete presentation.
[1][2]Assess while addressing life threats
Call for help immediately and assess airway, breathing, circulation and consciousness while monitoring progression. Identify and remove the trigger if possible without delaying care. Keep the patient lying down; cautiously adjust position if breathing requires it and prevent standing or walking. Record allergy history, medicines and symptom and intervention times for handover.
[2][3]Rapidly progressive airway, breathing or circulatory compromise after a compatible exposure may be anaphylaxis without urticaria. For adults, RCUK recommends 500 micrograms of intramuscular adrenaline into the anterolateral thigh: 0.5 mL of a 1 mg/mL solution. Repeat after five minutes if life-threatening problems persist. Do not extrapolate this dose to children.
[2][1]Give first-line treatment
Intramuscular adrenaline is first-line treatment for suspected anaphylaxis; early administration by trained personnel follows the protocol appropriate to age and situation. Antihistamines and corticosteroids must neither delay nor replace it when life-threatening features are present. Persistent breathing or circulatory compromise requires reassessment, protocol-based treatment and specialist support. Intravenous adrenaline belongs in experienced hands with appropriate monitoring.
[2][1]- Antihistamines and corticosteroids do not replace adrenaline for life-threatening compromise.
- Intravenous adrenaline requires expert teams and monitoring; never transfer an intramuscular dose to the intravenous route.
- After stabilisation, arrange risk-based observation, education, re-exposure prevention and allergy assessment.
Plan for recurrence and allergy assessment
Initial improvement does not justify immediate discharge: observation depends on severity, response and recurrence risk. Investigations, including tryptase when indicated, must never delay treatment; a normal result does not exclude anaphylaxis. Arrange allergy assessment, document the suspected trigger and provide a clear action plan. NICE NG258 recommends two in-date auto-injectors and practical training at discharge, except notably for easily avoidable drug allergy; arrange access with the team according to the local setting.
[4][1]A learning situation
FICTIONAL CASE · SELF-REFLECTION WITHOUT A SCORE
Minutes after receiving an antibiotic, a 34-year-old woman develops a hoarse voice, wheeze and faintness. No rash is visible. Someone suggests waiting for an antihistamine to work.
Which error should be prevented?
Read the reasoning
Waiting because there is no rash, or prioritising an antihistamine, would delay care for probable anaphylaxis. Call emergency assistance and have trained personnel give intramuscular adrenaline according to protocol, with appropriate positioning and monitoring. Investigation of the cause follows management of life-threatening features.
References and scope
- World Allergy Organization Anaphylaxis Guidance 2020 ↗
- Emergency treatment of anaphylaxis: Guidelines for healthcare providers — May 2021 ↗
- First Aid Guidelines — Resuscitation Guidelines 2025 ↗
- Anaphylaxis: assessment and referral after emergency treatment — NG258 ↗
Original educational synthesis for adult first-line practice. International references must be interpreted with the clinical setting and local care pathways. Independent human scientific review remains to be confirmed.