The objective of this study was to evaluate the efficacy and safety of cetirizine hydrochloride injection in the treatment of acute urticaria.The participants were randomized to receive cetirizine hydrochloride or diphenhydramine hydrochloride.
Age range: 18 - 65 years old (inclusive of the threshold value), gender not limited;
Diagnosed with acute urticaria (the definition of acute urticaria: spontaneous wheals and/or angioedema attacks ≤ 6 weeks);
At screening，the severity score of pruritus of the patient was ≥ 1 point ;
At screening，the degree score of wheals/erythema of the patient assessed by the investigator was ≥ 1 point ;
Patients in whom an antihistamine are contraindicated (such as those with angle-closure glaucoma, symptomatic benign prostatic hyperplasia, etc.);
Patients who used H1 antagonists (such as diphenhydramine, cetirizine, loratadine, fexofenadine, levocetirizine, desloratadine, etc.) within 2 hours before randomization;
Patients who used H2 antagonists (such as cimetidine, ranitidine, famotidine, roxatidine, etc.) within 2 hours before randomization;
Patients who used doxepin within 2 hours before randomization;