Background Cutaneous viral warts are benign epidermal proliferations caused by human papillomaviruses (HPVs). Despite treatment, a significant proportion of warts fail to resolve, becoming recalcitrant. Vitamin A (retinol) may disrupt the interplay of HPV replication and epithelial cell differentiation, allowing normal tissue to replace warts. Circulating retinol‐binding protein (RBP) concentrations highly correlate with retinol levels.

Aim We aimed at evaluation of serum RBP level in patients with recalcitrant cutaneous warts in order to assess its correlation with disease pathogenesis.

Methods Serum RBP level was measured by an ELISA technique in 50 patients with recalcitrant cutaneous warts and 30 apparently healthy controls.

Results Serum RBP level was significantly lower in patients with recalcitrant warts than the control group (P < 0.001). However, it did not differ regarding different clinical parameters in studied patients (P > 0.05 each). RBP is a reliable biomarker for significant early detection and discrimination between patients and healthy controls (P < 0.001) at a cutoff value ≤1034.6 μg/ml, with sensitivity and specificity (100% each).