Digital Dermatopathology of Scabies: HE-Compatible VIS–NIR Hyperspectral Imaging as a Label-Free Proof-of-Concept Approach

<b>Background:</b> Scabies, caused by <i>Sarcoptes scabiei</i> var. <i>hominis</i>, remains difficult to confirm histologically when parasites are sparse or fragmented. Conventional microscopy is particular but limited by small sample size, tissue destruction, and observer dependence. <b>Objective:</b> To evaluate visible-near-infrared hyperspectral imaging (VIS-NIR HSI) as a label-free optical method for detecting <i>S. scabiei</i> in human skin sections and to assess its compatibility with routine HE staining. <b>Methods:</b> Formalin-fixed, paraffin-embedded (FFPE) skin tissue from six patients with histologically verified scabies was analysed using VIS-NIR HSI (500-1000 nm). Unstained sections mounted on CaF₂ substrates and parallel HE-stained slides were imaged. Spectral datasets were processed by principal component analysis and segmentation to distinguish mite structures from epidermal and dermal compartments. <b>Results:</b> The chitin-rich mite exoskeleton exhibited a reproducible reflectance slope in the near-infrared range (R₈₅₀/R₅₅₀ > 1.5), clearly separating parasite from host tissue (R₈₅₀/R₅₅₀ < 1.0). PCA confirmed consistent cluster separation across all cases (ΔPC ≈ 3.7 ± 0.2). These contrasts remained detectable in HE-stained sections, validating applicability to conventional slides. <b>Conclusions:</b> VIS-NIR HSI enables reliable, label-free detection of <i>S. scabiei</i> mites in both unstained and HE-stained human skin tissue. By combining morphological and biochemical information in a single modality, HSI represents a promising adjunct to digital dermatopathology and may improve diagnostic sensitivity in challenging or atypical cases.