Hematological ratios in pediatric patients with alopecia areata based on a nationwide retrospective cohort study.

Our goal was to analyze hematological ratios in patients with pediatric alopecia areata (AA) and assess their potential as markers of disease exacerbation. A retrospective cohort study of 31,869 patients (aged 0–18) with AA was conducted using blood samples collected within 30 days of diagnosis and 12–18 months prior. Univariate and multivariable analyses were used to compare the hematological ratios among healthy controls, patients with mild AA, and patients with severe AA. Data were gathered from Israel’s Clalit database and Soroka Hospital, Beer Sheva, and represented both Arab and Jewish populations. The eosinophil/lymphocyte ratio (ELR), eosinophil/monocyte ratio (EMR), and eosinophil/neutrophil ratio (ENR) were elevated in patients with AA (0.11 vs. 0.10, p < 0.001; 0.75 vs. 0.57, p < 0.001; 0.12 vs. 0.10, p < 0.001, respectively). Elevated ELR increased the likelihood of AA by 3.31 times (95% CI: 2.20–5.01) and ENR by 2.61 times (95% CI: 1.86–3.69). Severe patients presented increases in the ELR (0.11 vs. 0.10, p < 0.01), ENR (0.10 vs. 0.09, p < 0.001), and EMR (0.70 vs. 0.63, p < 0.001). Elevated ENR was observed in severe patients 12–18 months prior to diagnosis. Eosinophilic ratios could serve as promising markers to study pathophysiology and potentially predict exacerbations of AA.