Efficacy and Safety of Chemoattractant Receptor-homologous Molecule Expressed on T Helper Type 2 (CRTh2) Antagonist AZD1981 in Chronic Idiopathic Urticaria (CIU) Antihistamines

The investigators are recruiting for a chronic hives study. This research is being done to test whether an investigational drug called AstraZeneca drug (AZD)1981 may be helpful for treating people with Chronic Idiopathic Urticaria who continue to have symptoms despite taking antihistamines. The word "investigational" means that AZD1981 is not approved for marketing by the Food and Drug Administration (FDA). The FDA is allowing the use of AZD1981 in this study. People with chronic hives lasting for at least 6 months and without a known cause may join. The study involves 6 visits over 8 weeks. Approximately 48 participants expected to take part in this study at the Johns Hopkins Asthma and Allergy Clinic. All participants will be treated with the study medication and/or placebo for 8 weeks. The results of this trial may have a benefit others with Chronic Idiopathic Urticaria who don't respond well to antihistamines by generating experience and data to support the design of a larger, multicenter trial investigating the efficacy of AZD1981 in treating antihistamine refractory CIU.