Biomarkers to predict therapeutic response in chronic spontaneous urticaria: a review

Chronic spontaneous urticaria (CSU) is a relatively common dermatological disorder characterized by sudden and unpredictable onset of pruritic wheals and/or angioedema, for more than six weeks. It is a mast cell-mediated histaminergic disorder, considerably worsening patients' quality of life. Current treatment options include anti-histamines, omalizumab and cyclosporine, in a step-wise algorithmic approach, aimed at complete symptom control. Patients do not respond uniformly to these therapeutic options due to phenotypic and endotypic heterogeneity, and often remain uncontrolled/poorly controlled. Recent research is focused on identifying certain biomarkers to predict therapeutic response and facilitate patient-targeted personalized treatment, for maximum benefit. The current article summarizes various biomarkers explored to date, and also elaborates their role in predicting therapeutic response to anti-histamines, omalizumab and cyclosporine, in CSU patients. High disease activity, elevated CRP/ESR and elevated D-dimer are the most important predictors of non/poor-response to antihistamines. Low and very low baseline IgE, elevated CRP/ESR, ASST+, BAT/BHRA+, basopenia, eosinopenia, and elevated D-dimer are predictors of poor and good response to omalizumab and cyclosporine, respectively. Additionally, normal or slightly elevated baseline IgE and FceR1 overexpression are predictors of a faster response with omalizumab. However, none of these predictors have so far been completely validated and are not yet recommended for routine use. Thus, large-scale prospective studies are needed to confirm these predictive biomarkers and identify new ones to achieve the goal of personalized medicine for CSU.