Evaluation of Pharmacological Treatments for Acute Urticaria: A Systematic Review and Meta-Analysis.

Background: The effectiveness and safety of pharmacological treatments for acute urticaria remain unclear.

Objective: To systematically review and meta-analyze the efficacy and safety of pharmacological treatments for acute urticaria in emergency department (ED) and non-ED settings.

Methods: We searched electronic databases and gray literature up to July 8, 2023, without language restrictions. Randomized clinical trials (RCTs) relating to pharmacological interventions in patients with acute urticaria, regardless of age, were eligible for inclusion. The relevant outcomes of interest were the treatment efficacy and safety profiles. The results are presented as standardized mean differences (SMDs) or odds ratios (ORs).

Results: We identified 8 RCTs comprising 680 patients. Regarding the ED setting (2 trials, n = 118), intramuscular first-generation H1-antihistamine (fgAH) was more efficacious in decreasing pruritus symptoms (SMD, -0.38; 95% confidence interval [CI], -0.75 to -0.02) but had higher sedative effects than H2-blockers. With comparable pruritus symptom improvement (2 trials, n = 295), intravenous second-generation H1-antihistamine (sgAH) had favorable clinical outcomes compared with intravenous fgAH in the ED setting with a lower risk of return to any ED/clinic (OR, 0.31; 95% CI, 0.12-0.83) and lower risk of any adverse event (OR, 0.24; 95% CI, 0.09-0.63). The efficacy of adjunctive therapy with a short course of systemic glucocorticosteroids in ED and non-ED settings remains unclear. No serious concerns regarding the safety profiles were observed in any of the treatment comparisons.

Conclusions: H1-antihistamine is a crucial and effective component of acute urticaria treatment, and intravenous sgAH is preferred as an initial treatment option.