Plasma Levels of D-dimer and Fibrin Degradation Products Correlate with Bullous Pemphigoid Severity: a Cross-sectional Study

Background: Bullous pemphigoid (BP), the most frequent blistering dermatosis in the elderly, is associated with increased mortality. The severity of BP can be assessed by detecting the anti-BP180 immunoglobulin G (IgG) titer, but the lab test is not available in many community clinics. BP patients are usually in a hypercoagulable state with increased levels of D-dimer and fibrin degradation products (FDPs). Objectives: To evaluate the use of D-dimer and FDPs in assessing BP severity. Methods: We compared the levels of plasma D-dimer, FDPs, eosinophils, and anti-BP180 IgG titer between 48 BP patients and 33 Herpes zoster (HZ) patients (control group). Correlational analyses were conducted to determine the relationships between the lab values and BP. Results: The plasma D-dimer and FDP levels were higher in BP patients than in HZ controls (D-dimer: 3297 ±2517 µg/L vs. 569.70 ±412.40 µg/L; FDP: 9.74 ±5.88 mg/L vs. 2.02 ±1.69 mg/L, respectively, P <0.0001). Significant positive correlations were found between D-dimer/FDP levels and BP severity markers (anti-BP180 IgG titer [D-dimer: r =0.3928, P =0.0058; FDP: r =0.4379, P =0.0019] and eosinophil counts [D-dimer: r =0.3625, P =0.0013; FDP: r =0.2880, P =0.0472]) in BP patients. We also found an association between FDP and urticaria/erythema lesions ( r =0.3016, P =0.0372), but no other BPDAI components. In 19 BP patients with complete remission after systemic glucocorticoid treatment, D-dimer and FDP levels decreased post-therapy (D-dimer: 5559 ±7492µg/L vs. 1738 ±1478 µg/L; P <0.0001; FDP: 11.20 ±5.88 mg/L vs. 5.13 ±3.44 mg/L; P =0.0003), where as they did not in BP patients with treatment resistant. Conclusion: Plasma D-dimer and FDP are convenient markers to evaluate BP severity.