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Dermatology
Urticaria and Angioedema
Built from Dermatology, 5th Edition
What’s inside
10 sections · 134 slides
Overview
- What this chapter covers
Definitions and Epidemiology
What counts as urticaria, how common it is, and who it affects
- Wheals and angioedema
- Appearance of wheals
- Appearance of angioedema
- Telling urticaria apart from look-alikes
- Wheals vs angioedema at a glance
- Two clinical starting points
- 8-22%
- Who gets urticaria
Pathogenesis
The mast cell, its triggers, and the bradykinin pathway behind angioedema without wheals
- The mast cell: main driver of urticaria
- What sets off degranulation
- From trigger to wheal
- Pathways that trigger mast cell degranulation
- What a mast cell releases
- Preformed and newly made mast cell mediators
- How mediators make blood vessels leak
- Autoantibodies that trigger mast cells
- IgE and autoantibody binding to the FcεRI receptor
- Circulating autoantibodies against other targets
- White blood cells in chronic urticaria
- Nerve signals and mast cells
- Two broad routes to a wheal
- Etiologies and pathomechanisms of wheals and/or angioedema
- Mast cell-dependent urticaria: IgE and physical triggers
- Cholinergic and vibratory urticaria mechanisms
- Why chronic urticaria is often 'idiopathic'
- Mast cell-independent urticaria
- C1 inhibitor deficiency causes a different kind of swelling
- Bradykinin build-up in C1 inhibitor deficiency
- Bradykinin pathway in hereditary and drug-induced angioedema
- HAE with normal C1 inhibitor activity
- Acquired C1 inhibitor deficiency and ACE inhibitor angioedema
Clinical Features
Classifying urticaria, and the many patterns it can take
- Classifying urticaria in the clinic
- Urticaria – clinical classification and differential diagnosis
- Defined by how long it lasts
- Acute vs chronic: what the numbers show
- Causes of acute urticaria
- What acute urticaria teaches us
- Causes of chronic urticaria
- Spontaneous urticaria: who and how it presents
- Typical spontaneous urticaria
- Annular and arcuate wheals
- Central pallor within annular wheals
- Comorbidities linked to chronic spontaneous urticaria
- How systemic disease can tint urticaria's colour
- Urticaria triggered by viral infection
- Inducible urticarias: triggered from outside
- Classification of inducible urticarias by the eliciting stimulus
- How inducible urticarias overlap and combine
- Dermographism: 'skin writing'
- Linear wheals of symptomatic dermographism
- Rarer forms of dermographism
- Delayed pressure urticaria
- Deep swelling of delayed pressure urticaria
- Vibratory angioedema
- Heat contact urticaria
- Cold urticaria: an overview
- Ice cube test for cold urticaria
- Cold urticaria subtypes
- Cholinergic urticaria: triggered by sweating
- Cholinergic urticaria after a hot bath
- Exercise-induced anaphylaxis and adrenergic urticaria
- Solar and aquagenic urticaria
- Contact urticaria
- Food contact hypersensitivity (oral allergy) syndrome
- Angioedema without wheals: think differently
- Drug-induced angioedema
- Angiotensin receptor blockers and sacubitril-valsartan
- Hereditary angioedema types I and II
- HAE with normal C1 inhibitor activity
Distinctive Syndromes
Rare disorders that present with urticaria-like lesions but need their own diagnosis and treatment
- Cryopyrin-associated periodic syndromes (CAPS)
- Other hereditary periodic fever syndromes
- Schnitzler syndrome
- Other acquired syndromes with urticarial rash
- Urticarial vasculitis
- Urticarial vasculitis lesions
- Urticarial vasculitis
- Urticarial vasculitis (continued)
- Urticarial vasculitis (continued)
Pathology
What a skin biopsy of urticaria actually shows
- Histology of ordinary urticaria
- Microscopic appearance of a spontaneous wheal
- Neutrophilic urticaria and neutrophilic urticarial dermatosis
- Neutrophilic urticarial dermatosis in lupus
Diagnosis and Differential Diagnosis
History, examination, and when to reach for tests
- Conditions that mimic urticaria
- Urticaria multiforme in children
- The essential history and examination
- Circling a lesion to time its duration
- Investigating acute urticaria
- Investigating chronic urticaria
- Testing for autoimmune urticaria
- Tests employed for autoimmune urticaria
- Tests employed for autoimmune urticaria (continued)
- Autologous serum skin test in action
- How the autoimmune urticaria tests overlap
- Testing for physical (inducible) urticarias
- Confirming urticarial vasculitis
- Working up angioedema without wheals
- Algorithm for diagnosing angioedema
- Algorithm for diagnosing chronic urticaria
Treatment
A stratified, three-line approach for urticaria, plus separate care for C1 inhibitor deficiency
- The overall treatment strategy
- Stepwise management of urticaria
- First-line: H1 antihistamines
- Antihistamines for urticaria
- Antihistamines for urticaria (continued)
- Classic vs second-generation antihistamines
- Adding an H2 antagonist, and antihistamines in pregnancy
- Second-line therapies: when to add them
- Some second-line medications for chronic or physical urticaria
- Corticosteroids and epinephrine: rescue, not routine
- Doxepin and montelukast
- Dapsone, sulfasalazine, and colchicine
- Second-line options at a glance
- Non-drug approaches
- Third-line: omalizumab
- Third-line: cyclosporine and other immunosuppressives
- Treating C1 inhibitor deficiency: a different playbook
- Preventing hereditary angioedema attacks
Prognosis
What patients can expect over time
- Long-term outlook
- Key takeaways
References
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- References (continued)
- Dermatology, 5th Edition (2-Volume Set)