Background: Cold urticaria is a rare but severe and potentially lethal condition. It is primarily treated symptomatically with H(1) -antihistamines. However, patients have a variable response to these drugs and, to date, it has not been possible to predict readily the response to therapy of individual patients.
Objectives: To assess the severity of the cold urticaria in naive patients and the response to therapy of patients treated with increasing doses of an H(1) -antihistamine by measurement of critical temperature thresholds (CTT) for producing weals on the forearm.
Methods: This was a two-centre, hospital-based, double-blind, randomized, parallel-group study of patients with a confirmed diagnosis of cold urticaria of at least 6 months' duration. Patient groups received either a constant dose of desloratadine 5 mg daily for 6 weeks (n = 13), or escalating doses of desloratadine: 5 mg daily for the first 2 weeks, 10 mg daily for the second 2 weeks and 20 mg daily for the final 2 weeks (n = 15). Only one adverse event that appeared to be drug related was reported: mild fatigue after treatment with desloratadine 10 mg that lasted for about 3 weeks and resolved at the end of the study.
Results: The desloratadine 5 mg daily dose produced a submaximal reduction of mean CTT which remained relatively constant over 6 weeks. Dose escalation increased efficacy, the reduction in mean CTT at four-times the standard daily dose being significantly greater (P = 0·03) than with the standard dose. Individually, no patient became symptom free (CTT < 4 °C) on 5 mg, while two became symptom free on 10 mg and a further three on 20 mg desloratadine daily.
Conclusions: Measurement of CTT allows for individualized risk management and therapy in patients with cold urticaria.
© 2012 The Authors. BJD © 2012 British Association of Dermatologists.