Clinical Efficacy of Desloratadine in Chronic Urticaria

Abstract

Chronic urticaria (CU) is a common, often excruciating skin disease that can lead to severe deterioration in quality of life. Although the itchy, erythematous wheals associated with this disorder result in large part from the vasoactive and neural effects of histamine, other mediators are also involved in some types of urticaria. Wheals exhibit a perivascular infiltrate, with eosinophil accumulation occurring as early as 4 hours after the initial appearance of swellings. Pruritus, which many patients consider the most distressing feature of CU, is also a chronic manifestation of the late-phase response. In human cell cultures, desloratadine, a long-acting, selective histamine H₁ receptor antagonist, exerted balanced inhibitory effects on both the early- and late-phase allergic responses, binding with high affinity to the H₁ receptor in vitro and also attenuating the release or expression of chemokines, cytokines and cellular adhesion molecules. A recent 6-week multicentre, randomised, double-blind, placebo-controlled study showed that once-daily therapy with this nonsedating antihistamine (5 mg/day) significantly lessened the severity of pruritus, number and size of hives, and sleep disturbances and interference with daily activities in 190 patients with moderate to severe disease. These benefits were observed within hours after the first dose and were maintained throughout the 24-hour dosing interval and at each weekly visit. Interim results from a subsequent 4-week open-label trial indicated that approximately 50% of patients with moderate to severe CU at baseline were completely free of urticaria at study endpoint, and about 70% reported that they no longer experienced hives or pruritus at night, when CU symptoms tend to be most severe. Desloratadine thus constitutes a sound option for nonsedating therapy of CU.