What is the initial treatment for acute urticaria?

Initial Treatment for Acute Urticaria

Second-generation non-sedating H1 antihistamines are the first-line treatment for acute urticaria. 1, 2, 3

First-Line Treatment: Non-sedating Antihistamines

• Second-generation H1 antihistamines (cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, and mizolastine) are the mainstay of therapy for acute urticaria 4, 2, 3
• Patients should be offered at least two different non-sedating antihistamines, as responses and tolerance vary between individuals 4, 2
• For inadequate symptom control, increasing the dose up to 4 times the standard dose is recommended when potential benefits outweigh risks 1, 2
• First-generation antihistamines should generally be avoided due to sedation and anticholinergic effects 1, 5

Intravenous Options for Severe Cases

• For severe acute urticaria requiring intravenous treatment, intravenous cetirizine 10 mg has been shown to be as effective as intravenous diphenhydramine 50 mg, with benefits of less sedation, fewer adverse events, shorter time spent in treatment centers, and lower rates of return visits 6

Adjunctive Treatments

• Cooling antipruritic lotions, such as calamine or 1% menthol in aqueous cream, can provide symptomatic relief 4
• Short courses of oral corticosteroids may be beneficial for severe acute urticaria (e.g., prednisolone 50 mg daily for 3 days in adults), although lower doses are often effective 4, 1
• Parenteral hydrocortisone may be given as an adjunct for severe laryngeal edema and anaphylaxis, though its action is delayed 4

Special Considerations

• Identify and minimize aggravating factors such as overheating, stress, alcohol, and certain medications (aspirin, NSAIDs, codeine) 4, 3
• NSAIDs should be avoided in aspirin-sensitive patients with urticaria 4, 3
• ACE inhibitors should be avoided in patients with angioedema without wheals 4, 3
• For anaphylaxis with severe urticaria, intramuscular epinephrine is the first-line treatment 4, 1

Treatment Algorithm for Acute Urticaria

1. Start with a standard dose of second-generation H1 antihistamine 2, 7
2. If inadequate control within 24-48 hours, increase the dose up to 4 times the standard dose 1, 2
3. For severe symptoms or inadequate response, add a short course of oral corticosteroids 4, 8
4. For severe cases requiring intravenous treatment, consider IV cetirizine over IV diphenhydramine due to fewer side effects 6
5. For anaphylaxis, administer intramuscular epinephrine immediately 4, 1

Important Caveats

• Cetirizine may be sedating, especially at higher doses 4
• Mizolastine is contraindicated in clinically significant cardiac disease and when there is prolongation of the Q-T interval 4
• Desloratadine has the longest elimination half-life (27 hours) and should be discontinued 6 days before skin prick testing 4
• Patient education about the generally favorable prognosis for eventual recovery is important 4, 7