D1.510 - Fecal Calprotectin as a Marker for Differentiating Children with Atopic Dermatitis With and Without Food Allergy

Fecal calprotectin (FCP) is a biomarker of intestinal inflammation and has recently been proposed as a diagnostic biomarker of food allergy (FA) in children. The aim of this study was to compare FCP level in infants and children under 4 years old with atopic dermatitis (AD) with and without food allergy (FA).

The study included a total of 54 children (n = 26 AD without FA; n = 28 AD with FA), with a median age of 20 months in the AD without FA group (range 3–44 months) compared to 6 months in the AD with FA group (range 2–21 months; p = 0.001, Mann–Whitney U test). In all subjects, a complete blood count, total IgE, specific IgE to nutritive allergens, immunoglobulins, FCP and SCORAD score were assessed.

FCP was significantly higher in the AD with FA group (median 154.00 µg/g, IQR 58.25–483.00) compared to the AD without FA group (median 24.00 µg/g, IQR 20.00–43.75; U = 116.000, z = −4.304, p = 0.001). SCORAD was also higher in the AD with FA group (p = 0.012). The AUC for FCP was 0.841 (95% CI: 0.716–0.926, p < 0.0001), with an optimal cut-off value of 50.9 µg/g (sensitivity 82.14%, specificity 84.62%, Youden’s J = 0.6676). Logistic regression analysis demonstrated a strong predictive value of the FCP cut-off (OR = 25.33, 95% CI: 3.81–168.54, p = 0.001), with a protective effect of older age (OR = 0.85 per month, p = 0.004). FCP showed a positive correlation with SCORAD in the AD with FA group (ρ = 0.593, p = 0.001), but not in the AD without FA group (ρ = −0.149, p = 0.489). 

These results suggest that FCP may serve as a potential noninvasive biomarker for the identification of nutritional allergy in AD, particularly in early childhood, demonstrating high discriminative ability.