Intended for healthcare professionals

Practice Rational Testing

Investigating recurrent angio-oedema

BMJ 2011; 343 doi: (Published 24 October 2011) Cite this as: BMJ 2011;343:d6607
  1. Penny Fitzharris, clinical director, immunology ,
  2. Anthony Jordan, registrar, immunology
  1. 1Immunology Department, Auckland City Hospital, Auckland 1023, New Zealand
  1. Correspondence to: P Fitzharris pennyf{at}

Where do you start with investigating causes of angio-oedema? This article will guide you through key information and tests

Learning points

  • In acute angio-oedema a detailed history may show that a food, drug, or sting triggers acute angio-oedema

  • Stop angiotensin converting enzyme (ACE) inhibitors in any patient who develops angio-oedema

  • In recurrent angio-oedema without urticaria, consider conditions including angio-oedema induced by ACE inhibitors and C1 inhibitor deficiency. Screen for C1 inhibitor deficiency in these patients (including those taking ACE inhibitors) by measuring C4 levels, and if levels are low refer for confirmation of diagnosis

  • Chronic spontaneous urticaria associated with angio-oedema is unlikely to be IgE mediated, and investigation for the presence of specific IgE is rarely indicated

A 57 year old man visited his local emergency department with his fourth episode of non-itchy swelling affecting the tongue and mouth in the past four months. Previous episodes had resolved over one to two days without treatment. On this occasion the patient woke from sleep and had difficulty swallowing and speaking. He took an antihistamine, but it had no clear effect. Clinical examination confirmed non-erythematous swelling, mainly affecting the tongue and lips (fig 1). The airway was adequate on first assessment, with an oxygen saturation of 97% on room air, blood pressure 150/90 mm Hg, respiratory rate of 20 breaths/min, pulse 90 beats/min. No urticaria or other rash were present.

Fig 1 Angio-oedema affecting both lips (real case to illustrate scenario)

What is the next investigation?

This patient is most likely to have angio-oedema (box 1 describes this and the related conditions urticaria and anaphylaxis). Additional clinical information is essential to guide relevant investigation in angio-oedema. This patient had no history of urticaria. Swelling began hours after last eating, and he had taken no over the counter medications such as non-steroidal anti-inflammatory drugs, which may precipitate angio-oedema. He …

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