Clinical variables of severe chronic spontaneous urticaria from total IgE standpoint: a retrospective study

Background.Baseline total IgE levels have recently emerged as a prognostic factor for the clinical response to omalizumab in patients with severe chronic spontaneous urticaria (CSU). Objective. To investigate the main clinical features of patients with severe CSU from the standpoint of baseline total IgE. Methods. 153 patients (M/F 52/101; mean age 49,7 years) with severe CSU were studied. Based on IgE levels patients were divided into 5 subgroups and a ROC curve was built to define a threshold level for omalizumab response. Atopic status, thyroid autoimmunity, activation of the coagulation cascade, and response to omalizumab were studied as well. Results. The subgroups did not differ in terms of age and gender. Atopy prevailed in the subgroup showing elevated IgE. Thyroid autoimmunity and elevated D-dimer levels were similarly distributed in the five subgroups. 94 patients showed a prompt response to omalizumab. The likelihood of a prompt response was higher in males (p less than 0.01). In the subgroup showing the lowest IgE levels only 10% responded promptly to the drug; these proportions were 60%, 65%, 81% and 83% in the remaining groups. 66% of those in group A did not respond at all to omalizumab. A threshold IgE level of 18 IU/ml was detected for omalizumab response. Conclusions. Baseline total IgE show a high high prognostic value for omalizumab response with a threshold level of 18 IU/ml. Males seem more responsive to omalizumab. Most patients show a mixed clinical picture where signs of atopic status co-exist with signs of an autoimmune disease.