How to prescribe antihistamines for chronic idiopathic urticaria: desloratadine daily vs PRN and quality of life

Chronic idiopathic urticaria (CIU) impairs quality of life (QoL). Currently, no consensus exists regarding how second-generation H-1-antihistamines (proven to control CIU symptoms) should be taken long-term: as daily treatment or only when symptoms return (PRN). We sought to determine which regimen improves or better maintains QoL in CIU: desloratadine (DL) daily or PRN. Subjects with CIU initially responding to DL 5 mg/day for 4 weeks were randomized for an additional 8 weeks, to DL 5 mg/day (arm 1: 'continuous', n = 46) or to DL only on days when urticarial wheals were present (arm 2: PRN, n = 60). To ensure blinding, treatment was presented in both arms as a combination of daily treatment (arm 1: DL; arm 2: placebo), plus a rescue tablet (arm 1: placebo; arm 2: DL) to be taken only in case of symptoms. The main outcome measure was QoL assessed by the VQ-Dermato, a validated French QoL instrument, and the Dermatology Life Quality Index (DLQI). At 4 and 8 weeks after randomization, subjects taking continuous DL showed statistically significant improvements in VQ-Dermato Global Index score (P = 0.001 and P = 0.016, respectively) and dimension scores for daily living activity, mood state, and social functioning vs subjects taking DL PRN. Improvement in DLQI score at Week 4 was also significantly greater with continuous DL (P = 0.001). Continuous daily therapy with DL 5 mg is a better regimen than PRN treatment to maintain or improve QoL in subjects with CIU.