Characteristic differences in barrier and hygroscopic properties between normal and cosmetic dry skin. I. Enhanced barrier analysis with sequential tape-stripping. Lu N. et al. Int J Cosmet Sci. 2014 Apr;36(2):167-74. doi: 10.1111/ics.12112. Epub 2014 Jan 31.
People with Atopic Dermatitis usually complain of rough dry skin and this is clinically called xerosis.
In the general population as well as in Atopics, this skin roughness occurs in unaffected skin and is due to anomalies of the upper part of the epidermis (called Stratum Corneum (SC))
The authors performed a study 64 healthy Caucasian female subjects with normal and xerosis:
-skin visually assessed and examination of the SC with tape stripping (Tape stripping removes the SC from the rest of the epidermis)
-measurement of trans-epidermal water loss (TEWL) was done after 5, 10, 15, 20th tape-strips.
-protein mass examined from tape strips – there was an inverse linear relationship between the quantity of protein removed and the TEWL. In other words, the bigger the barrier defect, the lower the amount of protein in the SC.
-SC thickness was calculated – it was shown to be thicker in xerotic skin.
CONCLUSION
This study shows that the Stratum Corneum (SC) of cosmetically dry skin (xerosis) is thickened when compared with normal skin and decreased barrier properties (increased Trans-Epidermal Water Loss (TEWL); less protein)
COMMENT
It is as in a brick wall:
Normally bricks are tightly held together by mortar (cement)
However in Atopic Dermatitis, the cement is somehow incomplete (deficiency of filaggrin) which makes the bricks more separated from each other.
Subsequently, the wall occupies a bigger volume it is deficient in its function.
Article selection: Prof Dr Jean-Hilaire Saurat – dermatologist. Geneva, Switzerland
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