Health Dictionary
Reliable, easy-to-read patient information on common medical conditions ā written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Chronic idiopathic urticaria
Introduction
Synonyms and keywords: CIU
Overview
Overview
Chronic idiopathic urticaria (CIU) is defined as frequent (daily, or near daily) itching and wheals for 6 weeks or more in the absence of any known cause. The incidence is approximately 0.5% of the population.
Pathophysiology
Pathophysiology
There are 2 subgroups of patients.
Autoimmune chronic urticaria (AICU)
30%-50% of patients have IgG autoantibodies against either the high-affinity IgE receptor FcĪµR1 or, less commonly, IgE. These patients also have an increased risk of antithyroid autoantibodies. Establishing this diagnosis is helpful as these patients may benefit from immunotherapy.
Truly idiopathic chronic idiopathic urticaria
In 50% of patients no autoantibodies are detected.
Diagnosis
Diagnosis
Symptoms
About 90% of patients also have angioedema.
Laboratory studies
There are no convenient readily available diagnostic studies.
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]