Abstract
Background
Atopic dermatitis (AD) is known to have skin barrier dysfunction and impaired sweating. To assess the relationship between sweating and skin barrier function, we measured 2 parameters reflecting skin barrier function; transepidermal water loss (TEWL), and water holding capacity of stratum corneum. Sweating function was evaluated by quantitative sudomotor axon reflex test (QSART) system in AD patients and non-atopic controls.
Methods
Thirty-nine AD patients (21 males and 18 females, mean ± SD age 37.8 ± 10.9 years) and 37 normal controls (17 males and 20 females, mean ± SDage 34.9 ± 10.1 years) were enrolled in this study. For measurement of TEWL and water holding capacity of stratum corneum on axilla, cubital fossa, scapular, and elbow. By using the QSART in which the axon reflex is stimulated by acetylcholine iontophoresis we measured the axon reflex (AXR) sweating volume for 5 minutes on cubital fossa. The measurements were performed at room temperature (21–22°C) and at relative humidity of 54%.
Results
The AD patients showed higher TEWL and lower water holding capacity value compared with normal controls on all 4 points. And the AD patients showed lower volumes of AXR sweating than normal controls on cubital fossa. We could not find out correlation between TEWL and AXR sweating volume. The same result was observed between water holding capasity and AXR sweating volume. To our knowledge, elevated TEWL and decreased water holding capacity are believed to skin barrier dysfunction. It was surprising that we found positive correlation between TEWL and water holding capacity in AD.
Conclusions
The results of TEWL and water holding capacity suggest that the barrier function of stratum corneum is impaired in AD patients. On the one hand, further studies should be required to explain the unexpected correlation between TEWL and water holding capacity. Both TEWL and water holding capasity didn't correlate with AXR sweating volume. This appeared that the 2 factors are not under the influence of the AXR sweating at the same site.