A Study to Assess and Compare the Effects of 5 mg vs. 20 mg Desloratadine on the Development of Cold Urticaria Lesions

Inclusion Criteria: 1. Outpatients with ACU for more than 6 weeks. Urticaria symptoms must comprise wheal and itch. 2. History of beneficial effects of antihistaminic treatment. 3. Age between 18 and 75 years. 4. Female patients must be using a highly effective method of birth control (such as implants, injectables, combined oral contraceptives, some IUDs, sexual abstinence,vasectomised partner), or they must be postmenopausal, surgically sterilised, or hysterectomised. 5. Voluntarily signed written informed consent. Exclusion Criteria: 1. The presence of permanent severe diseases, especially those affecting the immune system, except ACU 2. The presence of permanent gastrointestinal condition which may influence the oral therapy (chronic diarrhoea diseases, congenital malformations or surgical mutilations of gastrointestinal tract) 3. History or presence of epilepsy, significant neurological disorders, cerebrovascular attacks or ischemia 4. History or presence of myocardial infarction or cardiac arrhythmia which requires drug therapy 5. Evidence of severe renal dysfunction 6. Evidence of significant hepatic disease (liver enzymes twice the upper reference value) 7. History of adverse reactions to DL, loratadine, or other ingredients of the IMP 8. Presence of active cancer which requires chemotherapy or radiation therapy 9. Presence of acute urticaria, angioedema, or larynx edema 10. History or presence of alcohol abuse or drug addiction 11. Participation in any clinical trial within 4 weeks prior to enrolment 12. Commitment to an institution in terms of § 40 Abs. 1 Nr. 4 AMG 13. Intake of antihistamines or leukotriene antagonists within 7 days prior to the beginning of the study 14. Intake of oral corticosteroids within 14 days prior to the beginning of the study 15. Use of depot corticosteroids or chronic systemic corticosteroids within 21 days before beginning of the study 16. Pregnancy or breast-feeding