Definition & Etiology

Definition
– Urticaria: red, itchy, raised rash
– Distinct from angioedema: deeper swelling/disruption of the skin surface

Etiology
Acute (<6 weeks) – usually self-limiting:
– Viral infections
– Allergic reactions: food, bites, contact allergens
– Drugs: penicillin, aspirin, NSAIDs, Vaccinations
– Latex exposure

Chronic (>6 weeks):
– Chronic spontaneous urticaria: no clear association
– Autoimmune urticaria
– Chronic inducible urticaria (response to stimuli): triggered by hot/cold, exercise, emotions,
solar, vibratory contact, delayed pressure