Skin Barrier Function and Microtopography in Patients with Atopic Dermatitis

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease whose incidence is increasing. Skin barrier dysfunction plays an important role in this disease. It has been observed that AD patients have higher transepidermal water loss (TEWL) and lower stratum corneum hydration (SCH); however, there is little information about skin microtopography in this pathology. The objective of this study is to evaluate skin barrier dysfunction and structural changes in patients with AD. Methods: A cross-sectional study was conducted including patients with AD. Parameters of skin barrier function were measured (TEWL, temperature, erythema, pH, skin hydration, elasticity) and also other topographical parameters (scaliness, wrinkles, smoothness, surface, contrast, variance) in both healthy skin and flexural eczematous lesions. Results: A total of 32 patients with AD were included in the study. Flexural eczematous lesions had higher erythema (369.12 arbitrary unit (AU) vs. 223.89 AU, p < 0.001), higher TEWL (27.24 g/h/m² vs. 13.51 g/h/m², p < 0.001), lower SCH (20.3 AU vs. 31.88 AU, p < 0.001) and lower elasticity (0.56% vs. 0.65%, p = 0.05). Regarding topographic parameters, flexural eczematous lesions presented greater scaliness (5.57 SEsc vs. 0.29 SEsc, p = 0.02), greater smoothness (316.98 SEsm vs. 220.95 SEsm p < 0.001), more wrinkles (73.33 SEw vs. 62.15 SEw p = 0.03), greater surface area (836.14% vs. 696.31%. p < 0.001), greater contrast (2.02 AU vs. 1.31 AU p = 0.01), greater variance (6.22 AU vs. 4.96 AU p < 0.001) and a lower number of cells (105.5 vs. 132.5 p < 0.001) compared to unaffected healthy skin, reflecting a decrease in skin quality in AD patients. Conclusions: Both skin barrier function and skin topography are damaged in patients with AD, with differences between healthy skin and flexural eczema.