2.6. Skin assessment

Animal skin was macroscopically examined daily with a digital camera (NEX‐3, Sony, Tokyo, Japan) and the erythema index (EI) was quantified, corresponding to the intensity of skin redness, with Image J 1.53e software (NIH, Bethesda, Maryland). ³⁰ Skin barrier function was evaluated by quantifying TEWL using the closed chamber VAPO SCAN (AS‐VT100RS, Asch Japan Co. Ltd., Tokyo, Japan) and skin surface pH was measured with a digital glass electrode (Hanna Instruments, HI 981037, Japan). These were measured on day 0, before treatment (normal barrier function values) and after SLS challenge (compromised barrier function values), on day 3 (after treatment), and then every day up to day 7. Three repeat measurements were recorded at the same anatomical location.