Refractory Chronic Urticaria in Adults: Clinical Characterization and Predictors of Severity

Abstract

Background: Chronic urticaria (CU) is defined as recurrent urticaria lasting for more than 6 weeks. Objectives: We aimed to characterize the phenotypes of patients with CU refractory to standard dose anti-H1 antihistamine treatment and search for clinical predictors of poor disease control.Methods: Retrospective collection of data regarding clinical characteristics, manifestations, comorbidities, treatment, and disease control of all adult refractory CU patients presenting to the Allergy and Immunology Department during one year. Descriptive and inferential analysis was performed to search for factors associated with disease control. Results: Sixty-one adult patients were included, 74% females, average age 44.5 years (18 to 84 years old). Most patients (78.7%) had initiated CU less than 1 year before enrolment. Chronic spontaneous urticaria (CSU) accounted for 55.7% of the patients and chronic inducible urticaria (ClndU) for 44.3%. Angioedema was present in 55.7% of the patients. Evidence for autoimmunity (positive anti-thyroid peroxidase antibodies, anti-nuclear antibodies or autologous serum test) was found in 45.2% (n=19) of 42 tested patients. High C-reactive protein was presenti in 14.3% (n=6) of 42 patients evaluated; half of these also had positive antinuclear antibodies. Forty-six patients (75.4%) had at least one significant exacerbation, requiring medical appointment, emergency room, hospitalization or job absenteeism. The number of exacerbations correlated with the presence of angioedema (p=0.022), with a recent diagnosis (<1 year), and with higher UAS7 severity (p=0.006). ClndU associated with poor symptom control (p=0.022) but had less exacerbations requiring medical observation or hospitalization (p=0.015). Conclusions: About half of the patients with CU presented autoimmunity. UAS7 severity and Angioedema are associated with disease exacebations. UAS7 and UCT presented unequal accuracy, with UAS7 better associating with the occurrence of exacerbations and treatment dosis. Accurate diagnostic tests, namely autoimmune parameters and inflammatory markers, should be recommended in some individual cases.