© 2005 The International Society of Dermatology International Journal of Dermatology 2006, 45, 469–474 469 Abstract Background Chronic idiopathic urticaria (CIU) is defined by the almost daily presence of urticaria for at least 6 weeks without an identifiable cause. Symptoms include short-lived wheals, itching, and erythema. CIU impedes significantly a patient’s quality of life (QoL). Levocetirizine is an antihistamine from the latest generation approved for CIU. Aim To investigate the efficacy of levocetirizine, 5 mg, and placebo for the symptoms and signs of CIU, as well as for the QoL and productivity. Methods The primary criteria of evaluation were the pruritus severity scores over 1 week of treatment and over 4 weeks. The QoL was assessed via the Dermatology Life Quality Index (DLQI). Results Baseline pruritus severity scores were comparable in the two treatment groups (2.06 ± 0.58). After 1 week, levocetirizine was superior to placebo and demonstrated a considerable efficacy (difference = 0.78, P < 0.001). This efficacy was maintained over the entire study period (4 weeks, P < 0.001). The number and size of wheals were considerably reduced compared with placebo over 1 week and over the total treatment period (P ≤ 0.001). This was paralleled by an improvement in the QoL (DLQI: 7.3 units in the levocetirizine group and 2.4 units in the placebo group) and a higher productivity at work in the levocetirizine group (3.0 workdays lost per patient per month in the placebo group, 0.3 in the levocetirizine group). No unexpected adverse events occurred. Conclusions Levocetirizine, 5 mg once daily, is an effective treatment for CIU, characterized not only by a rapid and sustained response, but also by an important improvement in QoL. Blackwell Publishing, Ltd. Oxford, UK IJD International Journal of Dermatology 1365-4632 Blackwell Publishing Ltd, 2004 45 Pharmacology and therapeutics Levocetirizine in chronic idiopathic urticaria Kapp and Pichler Pharmacology and therapeutics Levocetirizine is an effective treatment in patients suffering from chronic idiopathic urticaria: a randomized, double-blind, placebo-controlled, parallel, multicenter study Alexander Kapp, MD, PhD, and Werner J. Pichler, MD From the Department of Dermatology and Allergology, Hannover Medical University, Hannover, Germany, and Clinic for Rheumatology and Clinical Immunology/ Allergology, Inselspital Freiburgstrasse, Bern, Switzerland Correspondence Alexander Kapp, MD, PhD Department of Dermatology and Allergology Hannover Medical University Ricklinger Strasse 5 D-30449 Hannover Germany E-mail: kapp.alexander@mh-hannover.de Introduction Chronic urticaria is a common dermatologic disorder with an estimated lifetime prevalence of 0.5% across all populations studied. 1 General practitioners and specialists have to deal with the challenge of treating the symptoms and ensuring a decent quality of life to their patients. New treatments are being developed, but antihistamines remain the cornerstone of the therapeutic approach. 2 During recent years, new anti- histamines have been marketed and have been indicated in the treatment of urticaria, with the benefit of a better safety profile. 3 Levocetirizine (Xyzal®) is one of the latest generation of antihistamines that has recently become available on the Euro- pean market. Levocetirizine is the optical isomer of cetirizine, with a twofold superior affinity for the H 1 histamine receptor and superior pharmacokinetic and pharmacodynamic prop- erties. 4,5 Our purpose was to compare the therapeutic effect of levocetirizine, 5 mg, with placebo in a population of patients suffering from chronic idiopathic urticaria (CIU) as defined by the recent international guidelines. 6 Chronic urticaria is often associated with impairment of daily activities and health-related quality of life (HRQoL). 7 The relative absence of data in this domain was an incentive to further explore this aspect of the disease. The Dermatology Life Quality Index (DLQI) questionnaire has been developed to assess the impairment of HRQoL associated with various dermatologic conditions. 8 A particular interest of this study was to assess how the alleviation or improvement of symp- toms translates into perceptible improvement of a patient’s quality of life and a decrease in the burden to society. Materials and Methods Study design This was a 4-week, randomized, double-blind, placebo-controlled, parallel, multicenter study. Nineteen centers (16 in Germany and three in Switzerland) participated in the study. After screening