Background: Many trials have reported that bloodletting therapy is effective when treating chronic urticaria. There are currently no systematic reviews of bloodletting therapy for chronic urticaria.

Objective: The aim of this review is to assess the effectiveness and safety of bloodletting therapy for chronic urticaria.

Methods: A systematic review and meta-analysis of randomized controlled trials were performed. Disease activity control was assessed as the primary outcome. Response rate, recurrence rate, and adverse events were assessed as secondary outcomes.

Results: Seven studies with 512 participants were included. One trial showed a significant difference between bloodletting therapy plus medicine and medicine alone in disease activity control (MD 0.67; 95% CI 0.03 to 1.31; p=0.04). Six trials (372 participants) showed a significant difference between bloodletting therapy and pharmacological medication in response rate (RR 1.10; 95% CI 0.97-1.26; P =0.15). Two studies (170 participants) showed a significant difference between bloodletting therapy plus pharmacological medication and pharmacological medication in response rate (RR 1.34; 95% CI 1.10-1.63; p=0.003). Two studies (126 participants) reported a statistically significant difference between bloodletting therapy and pharmacological medication in recurrence rate. No serious adverse events related to bloodletting therapy were reported.

Conclusions: Bloodletting therapy might be an effective and safe treatment for chronic urticaria, but the evidence is scarce. More high quality trials are needed in the future.