Elevated fecal calprotectin levels in psoriasis: association with disease severity.

PURPOSE: Psoriasis is a cutaneous and systemic inflammatory disease. Identifying biomarkers that accurately reflect disease activity and inflammatory burden has become an important area of research in psoriasis. Fecal calprotectin (FC), a noninvasive biomarker of neutrophil-driven inflammation, may provide complementary information in psoriasis. We aimed to assess FC levels in patients with psoriasis and to explore their association with disease characteristics. MATERIALS AND METHODS: Eighty adult psoriasis patients and 80 healthy volunteers were included in this case-control study. None of the participants had active infection, pregnancy, malignancy, or known gastrointestinal disease. Demographic data, gastrointestinal complaints using the Gastrointestinal Symptom Rating Scale, psoriasis severity using the Psoriasis Area and Severity Index (PASI) and Body Surface Area (BSA), and psoriasis characteristics were recorded. FC levels were measured by ELISA. ROC curve analysis and multivariable linear regression were performed. RESULTS: Median FC levels were significantly higher in psoriasis patients compared to controls (235.0 [11.2-2100.0] µg/g vs. 44.6 [6.7-711.6] µg/g, p < 0.001). ROC analysis demonstrated good discrimination between psoriasis patients and controls (AUC = 0.865), with an optimal cutoff value of 102 µg/g (sensitivity 87.5%, specificity 73.7%). FC levels showed a weak but significant positive correlation with psoriasis severity. Patients with FC levels >250 µg/g had significantly higher PASI and BSA scores than those with lower FC levels. In multivariable analysis, PASI remained independently associated with FC levels. CONCLUSION: Psoriasis patients demonstrated elevated FC levels. FC levels were associated with psoriasis severity, suggesting that higher FC levels may parallel greater cutaneous disease burden. Baseline FC assessment requires further validation before clinical implementation.