Patients with urticaria make up a large proportion of the referrals to allergy clinics. There are many causes of urticaria and it is the clinical history which is most important when attempting to identify potential causes; however, urticaria is very often idiopathic. Urticaria is widely used to describe an eruption of weals. It is now also increasingly being used to define a disease characterized by short-lived itchy weals, angio-oedema orboth together.
Most patients with urticaria do not have systemic reactions, but allergic and some physical urticarias may occasionally progress to anaphylaxis. Conversely, urticaria is often a feature of anaphylactic and anaphylactoid reactions. Classification Classification of urticaria may guide appropriate investigation and management. For clinical purposes it is often more helpful to classify urticaria by presentation than by aetiology, which is…
