Treatment of chronic spontaneous urticaria with an inadequate response to H1-antihistamines: an expert opinion

Chronic spontaneous urticaria (CSU) is characterized by the sudden, continuous or intermittent appearance of pruritic wheals (hives), angioedema, or both for six weeks or more, with no known specific trigger. The international EAACI/GA²LEN/EDF/WAO urticaria guideline advises standard-dose, second-generation H₁-antihistamines as first-line therapy. However, H₁-antihistamine treatment leads to absence of symptoms in fewer than 50% of patients. Updosing of second-generation H₁-antihistamines (up to fourfold) as recommended by the EAACI/GA²LEN/EDF/WAO urticaria guideline as second-line therapy, can improve response, but many patients remain symptomatic. Definitions of response are often subjective and a consensus is needed regarding appropriate treatment targets. There is also an unmet need for biomarkers to assess CSU severity and activity and to predict treatment response. The EAACI/GA²LEN/EDF/WAO urticaria guideline recommends add-on omalizumab, ciclosporin A (CsA), or montelukast third-line treatment in patients with an inadequate response to high-dose H₁-antihistamines. Omalizumab is currently the only licensed systemic biologic for use in CSU. Both omalizumab and CsA are effective third-line CSU treatments; montelukast appears to have lower efficacy in this setting. Omalizumab carries a label warning for anaphylaxis, although no cases of anaphylaxis were reported in the phase III trials of omalizumab in CSU and it is generally well tolerated in patients with CSU. Omalizumab arguably has a better safety profile than CsA.