THE EFFECT OF CETIRIZINE ON SYMPTOMS AND WEALING IN DERMOGRAPHIC URTICARIA

The effect of cetirizine, 10 mg at night, on dermographic urticaria, w as studied in 19 patients. The study design was a randomized, double-b lind, crossover comparison with placebo, each treatment being given fo r 7 days. Patients kept a daily diary of itch and weal severity (100-m m linear analogue scale), and recorded sleep disturbance. The dermogra phic weal response was measured objectively with a spring-loaded stylu s, and the weal threshold calculated from the force/response curve. Th ere was a small, insignificant subjective response to placebo, but no objective response. On cetirizine, the subjective assessment of wealin g was reduced from 34.3+/-6.7 (mean+/-SEM, 0-100 scale) to 16.8+/-4.1 (P=0.02), itch was reduced from 43.2+/-6.6 to 19.4+/-4.1 (P=0.001), an d nights disturbed from 46.2 to 8.8% (P=0.03). There was a shift to th e right in the position of the force/response curve, and the wealing t hreshold increased from 24.6+/-3.2 to 54.7+/-4.4 g/mm2 (P = 0.00001), but there was no correlation between change in itch scores and wealing threshold. Cetirizine 10 mg daily is an effective treatment in dermog raphic urticaria, and its usefulness will depend on the prevalence of unwanted effects.