A 40-year-old woman has chronic spontaneous urticaria (CSU) for 8 months. She is on maximally dosed non-sedating H1-antihistamines (cetirizine 20 mg/day) without adequate control. She has positive autologous serum skin test (ASST). The next appropriate step per current EAACI guidelines is:
- A Add H2-antihistamine (ranitidine)
- B Oral prednisolone 40 mg/day long-term
- C Omalizumab 300 mg subcutaneous monthly ✓
- D Cyclosporine 3–5 mg/kg/day
Correct answer: C. Omalizumab 300 mg subcutaneous monthly
Explanation
EAACI/WAO/EADV guidelines for CSU follow a stepwise approach: Step 1 — licensed dose non-sedating H1-AH; Step 2 — up to 4x dose H1-AH; Step 3 — add omalizumab (anti-IgE) 150–300 mg/month SC; Step 4 — add cyclosporine or other immunomodulators. Omalizumab (anti-IgE monoclonal antibody) binds free IgE and downregulates FcεRI on mast cells, reducing mast cell reactivity. It is highly effective in autoimmune (ASST-positive) and non-autoimmune CSU. H2 antagonists add minimal benefit. Cyclosporine is reserved for omalizumab-refractory cases (Step 4).
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
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Written and medically reviewed by the StethoPrep medical team.