Skin barrier cross-section Cross-section of the skin on a dental worker's hand: skin cells (bricks) sealed by lipid mortar. Sweat trapped under a glove soaks the outer layer, washing strips the mortar, moisture escapes and irritants get in. SURFACE · BACK OF THE HAND · UNDER THE GLOVE PHASE 1 · HEALTHY CROSS-SECTION, NOT TO SCALE Stratum corneum 10–20 layers of flat, dead cells.Your outer barrier. Lipid “mortar” Ceramides, cholesterol, fatty acidsseal the gaps between the bricks. Living epidermis Makes new cells that move up andflatten over about 4 weeks. Dermis Collagen and blood vessels. LEGEND Water Irritants Nitrile glove

Brick-and-mortar model of the stratum corneum: Elias PM, J Invest Dermatol 1983;80:44s–49s. Exposure: R&R Lotion blog, Glove Safety and Compatibility in the Workplace (2022). Illustration for education only.