Phys · general-medicine

Urticaria and Angioedema

Also known as hives · chronic spontaneous urticaria · CSU · chronic idiopathic urticaria · chronic autoimmune urticaria · physical urticaria · dermographism · cold urticaria · angioedema · hereditary angioedema · HAE · C1 inhibitor deficiency · ACE inhibitor angioedema · bradykinin-mediated angioedema · urticarial vasculitis · omalizumab · icatibant · lanadelumab

Consultant-physician guide to urticaria and angioedema: the lesion-duration rule (transient wheals less than 24 hours equals urticaria; persistent lesions with purpura equal urticarial vasculitis), the acute-versus-chronic classification (chronic spontaneous urticaria CSU as a mast-cell autoimmune disease), the pivotal angioedema branch point (with urticaria equals histamine-mediated; without urticaria equals bradykinin-mediated — hereditary angioedema HAE, ACE inhibitor, acquired C1-INH deficiency), the four-step EAACI treatment ladder (standard-dose H1, up to 4-fold H1, omalizumab, ciclosporin), the acute and prophylactic management of HAE (C1-INH concentrate, icatibant, lanadelumab), and the absolute rules that HAE does NOT respond to adrenaline and ACE inhibitors are never rechallenged.

high8 referencesUpdated 26 July 20268 min readVerification in progress

Practise this topic

On this page & tools

Your progress

Saved locally on this device.

Practise this topic

Target exams

FRACP DWEFRACP DCEMRCP Part 1MRCP Part 2MRCP PACESABIM Internal Medicine

Red flags

Angioedema WITHOUT urticaria or pruritus is bradykinin-mediated — think hereditary angioedema (C1-INH deficiency), ACE inhibitor-induced angioedema, or acquired C1-INH deficiency; adrenaline, antihistamines, and corticosteroids are NOT effective and giving repeated doses while the airway closes is a documented cause of death.Any wheal that lasts more than 24 hours, leaves bruising or residual pigmentation, or is painful rather than pruritic is urticarial vasculitis until proven otherwise — perform a 4 mm punch skin biopsy with immunofluorescence and check complement; this is a leukocytoclastic vasculitis, not ordinary chronic urticaria, and the management is different.Acute attacks of hereditary angioedema do NOT respond to adrenaline, antihistamines, or corticosteroids — give C1 inhibitor concentrate 20 units per kg IV or icatibant 30 mg SC immediately and secure the airway; laryngeal oedema is the leading cause of death.ACE inhibitor angioedema can occur years after starting therapy — any patient on an ACE inhibitor with lip or tongue swelling and no urticaria has ACE inhibitor angioedema until proven otherwise; stop the drug permanently and NEVER rechallenge.Cold contact urticaria can progress to anaphylaxis on cold water immersion — a documented cause of drowning; warn the patient explicitly, advise never to swim alone, and ensure adrenaline availability.An elevated serum tryptase (especially above 20 micrograms per litre) in recurrent unexplained urticaria or anaphylaxis suggests systemic mastocytosis or a clonal mast cell disorder — request bone marrow evaluation (KIT D816V mutation, CD25, tryptase stain).Extensive food and inhalant allergy panels are NOT indicated in chronic spontaneous urticaria — CSU is driven by autoimmunity or intrinsic mast cell activation, not IgE-mediated food allergy; broad panels produce false positives, drive unnecessary elimination diets, and delay guideline-directed treatment.Sedating first-generation antihistamines (promethazine, chlorpheniramine, hydroxyzine) impair cognition, reaction time, and sleep architecture even when the patient does not feel sleepy, and increase falls in older adults — the guideline explicitly recommends second-generation non-sedating agents for chronic urticaria.

Your progress

Saved locally on this device.

Practise this topic

Target exams

FRACP DWEFRACP DCEMRCP Part 1MRCP Part 2MRCP PACESABIM Internal Medicine

Red flags

Urticaria and Angioedema

Meet the patient

A 62-year-old man on ramipril for five years arrives in the emergency department with a swollen tongue and lips, no wheals, no itch. The team gives adrenaline, antihistamines, and hydrocortisone, and the swelling keeps climbing towards the airway. The single question that would have changed the management is the one that sorts every angioedema: is there urticaria or not?[1]

Hold that question and the rest slots into place — wheals with the swelling mean histamine and the drugs work; swelling alone means bradykinin and the drugs do not.[1]

Physician Medicine Pro

You have read the opening of this topic. The complete unit — every section and its primary-source references — is part of the Physician Medicine fellowship atlas.

References8Show ledger

[1]Zuberbier T, Abdul Latiff AH, Abuzakouk M, et al. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria Allergy, 2022.PMID 34536239
[2]Maurer M, Rosén K, Hsieh HJ, et al. Omalizumab for the treatment of chronic idiopathic or spontaneous urticaria N Engl J Med, 2013.PMID 23432142
[3]Zuraw BL Clinical practice. Hereditary angioedema N Engl J Med, 2008.PMID 18768946
[4]Baş M, Greve J, Stelter K, et al. A randomized trial of icatibant in ACE-inhibitor-induced angioedema N Engl J Med, 2015.PMID 25629740
[5]Sinert R, Levy P, Bernstein JA, et al. Randomized Trial of Icatibant for Angiotensin-Converting Enzyme Inhibitor-Induced Upper Airway Angioedema J Allergy Clin Immunol Pract, 2017.PMID 28552382
[6]Cicardi M, Banerji A, Bracho F, et al. Icatibant, a new bradykinin-receptor antagonist, in hereditary angioedema N Engl J Med, 2010.PMID 20818888
[7]Banerji A, Riedl MA, Bernstein JA, et al. Effect of Lanadelumab Compared With Placebo on Prevention of Hereditary Angioedema Attacks: A Randomized Clinical Trial JAMA, 2018.PMID 30480729
[8]Kaplan AP Chronic Spontaneous Urticaria: Pathogenesis and Treatment Considerations Allergy Asthma Immunol Res, 2017.PMID 28913986

Urticaria and Angioedema

high8 referencesUpdated 26 July 20268 min readVerification in progress

Meet the patient

Hold that question and the rest slots into place — wheals with the swelling mean histamine and the drugs work; swelling alone means bradykinin and the drugs do not.[1]

Physician Medicine Pro

You have read the opening of this topic. The complete unit — every section and its primary-source references — is part of the Physician Medicine fellowship atlas.

References8Show ledger

[1]Zuberbier T, Abdul Latiff AH, Abuzakouk M, et al. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria Allergy, 2022.PMID 34536239
[2]Maurer M, Rosén K, Hsieh HJ, et al. Omalizumab for the treatment of chronic idiopathic or spontaneous urticaria N Engl J Med, 2013.PMID 23432142
[3]Zuraw BL Clinical practice. Hereditary angioedema N Engl J Med, 2008.PMID 18768946
[4]Baş M, Greve J, Stelter K, et al. A randomized trial of icatibant in ACE-inhibitor-induced angioedema N Engl J Med, 2015.PMID 25629740
[5]Sinert R, Levy P, Bernstein JA, et al. Randomized Trial of Icatibant for Angiotensin-Converting Enzyme Inhibitor-Induced Upper Airway Angioedema J Allergy Clin Immunol Pract, 2017.PMID 28552382
[6]Cicardi M, Banerji A, Bracho F, et al. Icatibant, a new bradykinin-receptor antagonist, in hereditary angioedema N Engl J Med, 2010.PMID 20818888
[7]Banerji A, Riedl MA, Bernstein JA, et al. Effect of Lanadelumab Compared With Placebo on Prevention of Hereditary Angioedema Attacks: A Randomized Clinical Trial JAMA, 2018.PMID 30480729
[8]Kaplan AP Chronic Spontaneous Urticaria: Pathogenesis and Treatment Considerations Allergy Asthma Immunol Res, 2017.PMID 28913986