Chronic Urticaria — SCE Dermatology MCQ

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ModerateInflammatory DermatosesChronic UrticariaSCE Dermatology

A 40-year-old woman has chronic idiopathic urticaria that has not responded to maximum-dose antihistamines. She is started on Omalizumab 300 mg monthly. After how many weeks should response be assessed?

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Correct answer: E — 12-16 weeks (response may be delayed)

While some patients respond to Omalizumab within days to weeks, NICE and EAACI/GA²LEN guidelines recommend assessing response at 12-16 weeks before concluding treatment failure. Some patients are 'slow responders' requiring 3-4 months for adequate response. The initial assessment at 12 weeks should evaluate whealing frequency, urticaria activity score (UAS7), and DLQI. If no response at 16 weeks, consider dose escalation (up to 600 mg monthly) or switching to Ciclosporin. Omalizumab (anti-IgE) works by reducing free IgE levels and downregulating FcεRI expression on mast cells and basophils. Response correlates with total IgE-mediated mast cell degranulation suppression.

Reference: NICE TA339 2015; EAACI/GA²LEN 2022