Acute urticaria is a common dermatological condition in emergency departments (EDs). The main therapy involves controlling pruritus with antihistamines. Although guidelines have promoted the use of corticosteroids in addition to H1 antihistamines, well-designed clinical trials evaluating this approach are scarce.

Adult ED patients with acute urticaria and a pruritus score > 5 on a visual analog scale (VAS) were randomized into three groups: (i) IV chlorpheniramine (CPM) treatment, (ii) IV CPM and IV dexamethasone (CPM/Dex) and (iii) IV CPM and IV dexamethasone with oral prednisolone as discharge medication for 5 days (CPM/Dex/Pred). The primary outcomes were self-reported pruritus VAS scores at 60 min after treatment. We also evaluated 1-week and 1-month urticaria activity scores for 7 days and adverse events.

Seventy-five patients (25 per group) were enrolled. The VAS scores of all groups decreased, but no significant difference was found in the VAS scores at 60 min after treatment between patients in the CPM group (n = 25) and those who received both CPM and dexamethasone (n = 50). At the 1-week and 1-month follow-ups, active urticaria (indicated by the urticaria activity score at 7 days) was more prevalent in the CPM/Dex/Pred group (n = 25) than in the control group.

The present study did not find evidence that adding IV dexamethasone improves the treatment of severe pruritus from uncomplicated acute urticaria. Oral corticosteroid therapy may be associated with persistent urticaria activity. Due to the lack of clinical benefits and the potential for side effects, using corticosteroids as an adjunctive treatment is discouraged.