Subclinical intestinal inflammation in psoriasis: a cross-sectional comparative study using fecal calprotectin

Psoriasis has been linked to inflammatory bowel disease and the gut-skin axis, but whether cutaneous psoriasis is associated with subclinical intestinal inflammation remains uncertain.

To evaluate fecal calprotectin (FC) and gastrointestinal symptom burden in adults with psoriasis and controls, with exploratory comparison by systemic treatment status.

This cross-sectional comparative study included 72 adults: 22 psoriasis patients receiving systemic therapy, 25 not receiving systemic therapy, and 25 controls. FC was measured by ELISA, gastrointestinal symptoms by the Gastrointestinal Symptom Rating Scale (GSRS), and psoriasis severity by the Psoriasis Area and Severity Index (PASI). Age- and sex-adjusted analyses used log-transformed FC.

Median (IQR) FC levels were 60.0 (30.0-263.1) µg/g in patients receiving systemic therapy, 48.4 (30.0-188.0) µg/g in those not receiving systemic therapy, and 57.6 (30.0-157.7) µg/g in controls, with no significant three-group difference (p = 0.554). In the pooled comparison, median FC was 53.1 (30.0-197.3) µg/g in psoriasis patients and 57.6 (30.0-157.7) µg/g in controls (p = 0.503). After age and sex adjustment, the geometric mean FC ratio was 1.30 (95% CI 0.74-2.28; p = 0.356). GSRS scores did not differ significantly between groups, and FC was not significantly associated with PASI or GSRS.

In this small, selected cohort of adults with predominantly mild cutaneous psoriasis and without known gastrointestinal disease or psoriatic arthritis, no statistically significant FC- or GSRS-based difference was detected between psoriasis patients and controls. Larger prospective studies are needed.