Chronic spontaneous urticaria (CSU) is increasingly recognized as a heterogeneous disease that may benefit from a more personalized diagnostic and treatment approach. The evolving role of biomarkers in guiding the management of CSU was discussed in a session at the recent 2026 AAAAI Annual Meeting.

Following this presentation, featured expert Jonathan A. Bernstein, MD, was interviewed by Conference Reporter Editor-in-Chief Tom Iarocci, MD. Clinical perspectives from Dr Bernstein on this discussion are presented here.

During my talk from the 2026 AAAAI Annual Meeting session titled “Chronic Spontaneous Urticaria (CSU) Biomarkers: To Order or Not to Order: That is the Question,” I discussed biomarkers and the prediction of treatment response in CSU. I began my presentation by emphasizing that the characterization of our patients with CSU begins clinically, through a good history and patient-reported outcome measures that are validated at baseline and then throughout the treatment course. From there, some baseline laboratory testing, as recommended in the guidelines, can serve as biomarkers to predict partial or poor response to high-dose nonsedating H₁ antihistamines for the treatment of a patient’s CSU.

With regard to this routine basic diagnostic testing, I discussed how a complete blood count with differential is reasonable, as is a thyroid-stimulating hormone (if not already done) and a CRP. Testing for CRP is particularly important because some evidence suggests that patients with CSU who have elevated CRP levels are less likely to respond to high-dose nonsedating H₁ antihistamines.

At this point in my presentation, I explained that the additional testing that has been shown in studies to predict poor or no response to omalizumab may be reasonable, including total IgE, the Chronic Urticaria (CU) Index, and autoantibody biomarkers such as anti-TPO. Although these tests are not 100% predictive, they can help guide treatment decisions for CSU (eg, when to choose omalizumab over dupilumab [a newer biologic therapy] or remibrutinib [an oral small-molecule therapy]). The biomarkers for predicting treatment response to omalizumab do not necessarily apply to dupilumab or remibrutinib, but this does not mean that other biomarkers will not emerge to help us understand who will or will not respond to these newer advanced therapeutics.

I ended my presentation at AAAAI 2026 by recapping that baseline laboratory testing and additional testing for CSU should be limited and personalized based on the patient’s history and the clinician’s decision-making process. I also emphasized the need for more information on how different subtypes of patients with CSU respond to dupilumab and remibrutinib, such as those with classic allergic-type urticaria—with total IgE levels within normal ranges and no autoantibodies—vs others with many autoantibodies and a presentation that is more consistent with chronic autoimmune urticaria.