Chronic spontaneous urticaria
Chronic spontaneous urticaria is recurrent wheals and/or angioedema occurring most days for 6 weeks or longer without an identifiable external trigger, frequently autoimmune. Diagnosis is clinical with minimal testing, and treatment follows a stepwise ladder from a second-generation H1 antihistamine, up-titrated fourfold, to omalizumab and then cyclosporine.
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What this article covers
- Overview
Definition: chronic spontaneous urticaria (CSU) is the recurrence of itchy wheals, angioedema, or both on most days for 6 weeks or longer without an identifiable external trigger.
- Epidemiology
Common: affects roughly 1 percent of people at some time, more often adults and women.
- Risk factors
Female sex and adult age. Autoimmune disease: especially autoimmune thyroiditis.
- Pathophysiology
Mast cell activation: dermal mast cell degranulation releases histamine, causing wheals and angioedema.
- Clinical features
Recurrent wheals: pruritic, raised lesions with surrounding flare, individually lasting under 24 hours.
- Differential diagnosis
Chronic inducible urticaria: wheals reproducibly triggered by a physical stimulus (cold, pressure, cholinergic), unlike chronic spontaneous urticaria which arises without an identifiable external trigger (Urticaria).
- Diagnosis
Diagnose clinically by the 6-week spontaneous pattern with minimal testing: CSU is a clinical diagnosis defined by recurrent wheals and/or angioedema on most days for 6 weeks or longer without an…
- Management
First-line, a second-generation H1 antihistamine at standard dose: for example cetirizine 10 mg PO daily, taken regularly rather than as needed.
- Complications
Impaired sleep and quality of life: the main burden of chronic disease.
- Prognosis
Self-limited over years: most patients remit within 1 to 5 years.
- Prevention
Take antihistamines regularly, not as needed, to prevent recurrent wheals.
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Related articles
- Urticaria
Urticaria is transient, pruritic, edematous wheals from mast cell histamine release, classified by duration into acute (under 6 weeks) and chronic (6 weeks or longer, usually spontaneous/idiopathic). Diagnosis is clinical with minimal testing, and treatment is stepwise second-generation H1 antihistamines up-titrated as needed, adding omalizumab for refractory chronic disease.
- Angioedema
Angioedema is self-limited, non-pitting swelling of the deep dermis and submucosa that follows one of two mechanisms: mast cell (histamine) mediated, which occurs with urticaria and responds to epinephrine and antihistamines, or bradykinin mediated, which occurs without urticaria and does not. Distinguishing the two determines whether treatment is allergic therapy or bradykinin-targeted therapy, and airway involvement is the central danger.
- Anaphylaxis
Anaphylaxis is an acute, potentially fatal systemic hypersensitivity reaction from massive mast cell and basophil mediator release, presenting within minutes as skin, respiratory, cardiovascular, and gastrointestinal involvement after allergen exposure. It is a clinical, treat-first diagnosis, and intramuscular epinephrine is the immediate life-saving therapy.