Study to Assess Efficacy, Safety and Mechanism of Rupatadine in Cold Urticaria

Inclusion Criteria: * Informed consent signed and dated * Reliable method of contraception for both women of childbearing potential as well as man during the study and 3 months thereafter. A highly effective method of birth control is defined as those which result in a low failure rate (i.e. less than 1% per year) when used consistently and correctly such as implants, injectables, combined oral contraceptives, some IUDs, sexual abstinence or vasectomised partner * Outpatients with CCU for more than 6 weeks. Urticaria symptoms must comprise wheal and itch after contact cooling of the skin. Provocation should be performed by application of Temptest®3.0 which allows for reproducible and standardized cold provocation tests and the identification of temperature and stimulation time thresholds. * Age 18 and above 18 years. * No participation in other clinical trials 1 months before and after participation in this study Exclusion Criteria: * Subjects who are inmates of psychiatric wards, prisons, or other state institutions. Existing or planned placement in an institution after ruling according to § 40 passage 1, number 4 AMG (Arzneimittelgesetz). * The presence of permanent severe diseases, especially those affecting the immune system, except urticaria and cold urticaria * The presence of permanent gastrointestinal condition which may influence the oral therapy (chronic diarrhoea diseases, congenital malformations or surgical mutilations of gastrointestinal tract) * History or presence of epilepsy, significant neurological disorders, cerebrovascular attacks or ischemia * History or presence of myocardial infarction or cardiac arrhythmia which requires drug therapy * ECG alterations of repolarisation (QTc prolongations \> 450ms) * Blood pressure \>180/100 mmHg and/or heart rate \>100/min. * Evidence of significant hepatic or renal disease (GOT and/or GPT 3 times above the upper reference value, serum creatinine 1.5 times above the upper reference value) * History of hypersensitivity or allergic reaction to rupatadine or its ingredients or any other antihistamine compounds. * Presence of active cancer which requires chemotherapy or radiation therapy * Presence of lactose and galactose intolerance or with glucose-galactose malabsorption * Simultaneous chronic spontaneous or physical urticaria that could interfere CCU clinical assessment * Intake of antihistamines or antileukotrienes within 7 days before beginning of the study * Intake of oral or depot corticosteroids within 14 days prior to screening visit * Use of systemic immunosupressants/immunomodulators like cyclosporine A, dapsone, methotrexate, mycophenolate, chloroquine, and comparable drugs within 28 days prior to screening visit. * Use of ketoconazole, erythromycin or potential inhibitors of the isoenzyme CYP3A4 of the cytochrome P450. * Currently abusing drugs or alcohol * Unwilling or unable to comply with the protocol * Pregnancy or breast-feeding