Introduction: The effect of 5 mg desloratadine for 4 days was tested with ice-cubes before and after 4 days of treatment in 12 patients with cold urticaria. They had been asked not to take any antihistamine for at least 4 days.
Objective: To find the effect of desloratadine on wheals and itching induced by cold.
Method: Ice-cubes in a thin plastic foil were placed on the inside of forearms for 0.5 to12 minutes. The time needed to produce a confluent urticaria, four or more small wheals and fewer than four small wheals were registered, together with the degree of itching.
Results: Before treatment a mean of 6.2 minutes was needed to cause a confluent urticaria, and itching occurred in seven of the patients. Four or more small wheals were observed after a mean of 3.7 minutes and fewer than four after a mean of 1.2 minutes. One 5 mg tablet of desloratadine was then given each morning for 4 days and the ice-cube test was repeated 4-5 hours after the last dose: no confluent urticaria and no itching occurred in any of the patients. Four or more small wheals were seen in two patients after 12 minutes, but there was no such reaction in the other 10 patients; in seven patients one to three small wheals developed. After 2-3 months of continued treatment four patients had noticed some wheals when out in the cold, but no itching. The symptoms of one patient with a delayed reaction after exposure to cold disappeared totally after a dose increase to 10 mg.
Conclusion: Desloratadine markedly inhibited the reactions to cold induced urticaria.