Chronic spontaneous urticaria (CSU) workup & ladder

Separates anaphylaxis and acute vs chronic urticaria, limits the workup, and walks the antihistamine→up-dose→biologic ladder. Links the UAS7 and UCT calculators.

Evidence tier: Guideline-derived.

Decision points

  • Acute (<6 weeks) or chronic (≥6 weeks)?
  • Refractory to up-dosed antihistamine?

Do-not-miss pitfalls

  • Do not order broad food/aeroallergen panels for CSU without a compatible immediate-food history.
  • Do not up-dose by stacking different antihistamines, up-dose a single second-generation agent (up to 4×).
  • Do not use chronic/maintenance systemic steroids; short rescue courses (≤10 days) only.
  • Do not mislabel bradykinin angioedema (no hives, antihistamine-unresponsive) as CSU.
  • Do not forget total IgE as an omalizumab-response biomarker in specialist care.

Evidence & citations

  1. Zuberbier T, Abdul Latiff AH, Abuzakouk M, et al. The international EAACI/GA²LEN/EuroGuiDerm/APAAACI guideline for the definition, classification, diagnosis, and management of urticaria. Allergy. 2022;77(3):734-766. PMID 34536239
  2. Bernstein JA, Lang DM, Khan DA, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol. 2014;133(5):1270-1277. PMID 24766875
  3. US FDA approvals: dupilumab for H1-antihistamine-refractory CSU (Apr 2025); remibrutinib (oral BTK inhibitor) for CSU (Sep 2025). FDA approvals

Clinician decision support. Verify against the cited source. Not a substitute for clinical judgment. 100% on-device; no patient data is stored or transmitted.