Correlation of C-Reactive Protein (CRP) levels with disease activity in chronic urticaria measured by Urticaria Activity Score-7 (UAS7)

Abstract

Background  The Urticaria Activity Score-7 (UAS7) questionnaire is used to assess clinical disease activity in chronic urticaria (CU). The questionnaire is subjective in nature, thus several reports suggest that an objective parameter, such as C-reactive protein (CRP), is needed to support disease activity assessment in CU.   Objective To investigate the relationship between CRP levels and clinical disease activity assessed using UAS7 in patients with CU.   Methods Our study was a quasi-experimental study, using the one group pretest-post test design. We recruited 18 patients aged 18-59 years old with CU who met inclusion and exclusion criteria. We assessed disease activity using the UAS7 questionnaire and measured CRP levels in the first visit. All subjects received an antihistamine (10 mg cetirizine) for 4 weeks and follow-up levels were measured post-treatment. Disease activity was assessed in weekly follow-ups using UAS7. Spearman analysis was used to calculate the correlation between CRP levels and disease activity.   Results We found an increase in CRP levels in more than a third of subjects (median 2.5 mg/L [range 0.1-8.7 mg/L]). Prior to antihistamine treatment, the median UAS7 score was 14 (range 5-32), and the median UAS7 score in the first to fourth week of treatment was 3 (range 0-14), 4 (range 0-14), 3 (range 0-14), and 2 (range 0-12), respectively. The relationship was statistically significant, with a coefficient of correlation of 0.529 (p=0.024).   Conclusion CRP levels were increased in CU patients. CRP levels were significantly correlated with clinical disease activity measured by UAS7. After receiving antihistamines, the proportion of subjects with high CRP levels decreased.