H1-antihistamines for chronic spontaneous urticaria

Area of Science:

• Dermatology
• Pharmacology
• Clinical Trials

Background:

• Chronic spontaneous urticaria (CSU) is a condition characterized by the sudden onset of itchy hives without a known external trigger.
• Effective management of CSU is crucial for improving patient quality of life.
• H1-antihistamines are a primary treatment modality for CSU.

Purpose of the Study:

• To evaluate the efficacy and safety of H1-antihistamines in treating chronic spontaneous urticaria (CSU).
• To compare the effectiveness of various H1-antihistamines against placebo and each other.
• To assess outcomes including complete urticaria suppression, quality of life improvements, and adverse events.

Main Methods:

• Conducted a systematic review of randomized controlled trials (RCTs) up to June 2014, searching multiple databases.
• Included RCTs comparing H1-antihistamines (single or combination therapy) against placebo or other active treatments.
• Analyzed primary outcomes: complete urticaria suppression, 'good or excellent' response, quality of life, and adverse events.

Main Results:

• 73 studies with 9759 participants were identified; 34 studies provided data for 23 comparisons.
• Cetirizine (10mg daily) showed effectiveness for complete urticaria suppression in both short-term and intermediate-term treatment compared to placebo.
• Desloratadine and levocetirizine also demonstrated efficacy in suppressing urticaria, with varying results based on dosage and treatment duration. Levocetirizine (5-20mg) was found more effective than desloratadine (5-20mg).

Conclusions:

• Several H1-antihistamines are effective for CSU at standard doses when compared to placebo.
• No single H1-antihistamine was definitively superior; evidence quality was often low due to small study sizes and limited data.
• Adverse event rates leading to withdrawal did not significantly differ between active treatments and placebo.