What is the treatment for acute urticaria after a hayride?

Treatment for Acute Hives After Hayride

Second-generation non-sedating H1 antihistamines are the first-line treatment for acute urticaria following a hayride, with options including cetirizine, desloratadine, fexofenadine, levocetirizine, and loratadine. 1, 2

First-Line Treatment

• Begin with a standard dose of second-generation non-sedating H1 antihistamine such as cetirizine, desloratadine, fexofenadine, levocetirizine, or loratadine 1, 2
• These medications are preferred over first-generation antihistamines due to their better safety profile and reduced sedation 2
• Specific options include:
  • Cetirizine 10 mg once daily 1
  • Fexofenadine 180 mg once daily 1
  • Loratadine 10 mg once daily 3
  • Desloratadine 5 mg once daily 2
  • Levocetirizine 5 mg once daily 2

Dose Escalation for Inadequate Response

• If symptoms persist after standard dosing, increase the dose up to 4 times the standard dose when benefits outweigh risks 1, 2
• For example, cetirizine can be increased from 10 mg daily to 20 mg twice daily if needed 1
• Allow 2-4 weeks to assess response before concluding treatment failure 4

Adjunctive Treatments

• For severe symptoms, a short course of oral corticosteroids may be considered 2
• Cooling antipruritic lotions (calamine or 1% menthol in aqueous cream) can provide symptomatic relief 1
• Identify and minimize aggravating factors such as overheating, stress, alcohol, and certain medications (aspirin, NSAIDs, codeine) 1, 2

Special Considerations

• If there are signs of respiratory involvement or anaphylaxis (difficulty breathing, throat tightness, dizziness), seek emergency medical attention immediately as epinephrine would be the first-line emergency treatment 4
• NSAIDs should be avoided in aspirin-sensitive patients with urticaria 1, 2
• ACE inhibitors should be avoided in patients with angioedema without wheals 1, 2

Treatment Selection Considerations

• Offer at least two different non-sedating antihistamines, as responses and tolerance vary between individuals 1, 2
• While diphenhydramine may have a marginally faster onset of action compared to second-generation antihistamines, its adverse effect profile (sedation, impaired concentration) makes second-generation antihistamines preferable 5
• In a comparative study, the combination of diphenhydramine with H2-antihistamines (ranitidine or cimetidine) showed efficient relief of urticaria symptoms 6

Common Pitfalls to Avoid

• Not increasing antihistamine dose before concluding treatment failure 2
• Using sedating first-generation antihistamines as primary therapy due to concerns about sedation and reduced concentration 4
• Prolonged use of oral corticosteroids, which should be restricted to short courses for severe acute urticaria 2
• Failing to identify and remove potential triggers 4
• Rare cases of H1-antihistamine-induced urticaria have been reported; if urticaria worsens after antihistamine treatment, consider switching to a different class of antihistamine 7

Prognosis

• Acute urticaria is typically self-limited and benign, though it can cause significant discomfort 8
• Most cases of acute urticaria resolve within days to weeks 9