Levels of C-Reactive Protein and D-Dimers in Chronic Urticaria as Markers of Severity

Objective: To assess C-reactive protein (CRP) and D-dimers as possible indicators of disease severity in individuals with chronic spontaneous urticaria (CSU), and to investigate additional inflammatory, allergic, and coagulation factors. Study Design: Cross sectional analytical study. Place and Duration of Study: Dermatology Department, Pak-Emirates Military Hospital Rawalpindi, Pakistan, from Feb 2023 to Jan 2024. Methodology: One hundred CSU patients and 100 age- and gender-matched healthy controls were enrolled. Disease severity was assessed using the Urticaria Activity Score over 7 days (UAS7). Serum CRP and D-dimer levels were measured by HS-CRP turbidimetric assay and ELISA, respectively. Additional parameters included serum IgE, prothrombin time (PT), and activated partial thromboplastin time (APTT). Data normality was tested, and correlations between biomarkers and UAS7 were analyzed using Pearson’s or Spearman’s correlation as appropriate. Results: Median CRP [8.7 (4.9–13.5) mg/L vs. 2.1 (1.3–4.0) mg/L; p<0.001] and D-dimer [468.8 (320.5–625.7) ng/mL vs. 190.4 (130.7–247.9) ng/mL; p<0.001] were significantly higher in CSU patients compared to controls. Moderate positive correlations were observed between UAS7 and CRP (r_s=0.62, p<0.001) and UAS7 and D-dimer (r_s=0.58, p<0.001). Female patients had significantly higher UAS7 scores and a higher frequency of elevated IgE, prolonged PT/APTT, and inflammatory markers. No significant correlation was found between CRP and D-dimer levels. Conclusion: CRP and D-dimer levels are elevated in CSU and correlate moderately with disease severity, suggesting their utility as adjunct biomarkers. Their limited specificity requires consideration of additional inflammatory, allergic, and coagulation markers in assessment.