Relation between skin micro-topography, roughness, and skin age

BACKGROUND

The topography of the skin surface consists of lines, wrinkles, and scales. Primary and secondary lines form a network like structure that may be identified as polygons. Skin surface roughness measurements are widely applied in dermatological research and practice but the relation between roughness parameters and their anatomical equivalents are unclear. This study aimed to investigate whether the number of closed polygons (NCP) per measurement field can be used as a reliable parameter to measure skin surface topography. For this purpose, we analysed the relation between skin surface roughness parameters and NCP in different age groups.

METHODS

Images of the volar forearm skin of 38 subjects (14 children, 12 younger, and 12 older adults) were obtained with the VisioScan VC98. The NCP was counted by three independent researchers and selected roughness parameters were measured. Interrater reliability of counting the number of closed polygons and correlations between NCP, roughness parameters, and age were calculated.

RESULTS

The mean NCP/mm² in children was 3.1 (SD 1.1), in younger adults 1.0 (SD 0.7), and in older adults 1.0 (SD 0.9). The interrater reliability was 0.9. A negative correlation of NCP/mm² with age was observed, whereas measured roughness parameters were positively associated with age. NCP/mm² was weakly related to skin roughness.

CONCLUSION

The NCP/mm² is a reproducible parameter for characterizing the skin surface topography. It is proposed as an additional parameter in dermatological research and practice because it represents distinct aspects of the cutaneous profile not covered by established roughness parameters.

Comparison of the effect of glycerol and triamcinolone acetonide on cumulative skin irritation in a randomized trial

BACKGROUND

So-called anti-irritants are added to cosmetic formulations because of their alleged beneficial effect on irritated skin. Documentation for these claims is often limited. However, glycerol has shown anti-irritant properties in experimentally induced irritation from sodium lauryl sulfate and nonanoic acid (NON). This study was designed to further substantiate that glycerol added to cosmetic formulations has an anti-irritant effect on experimentally induced skin irritation.

OBJECTIVE

We sought to compare glycerol with triamcinolone acetonide as treatments for cutaneous irritation in human volunteers.

METHODS

Irritation was induced by 3 daily arm washes for a week with 10% sodium lauryl sulfate on one arm and 30% NON on the other. To maintain irritation, for the next 12 days volunteers washed their arms twice daily with the irritants. Treatments were applied immediately after washing. The treatments (including vehicle and no treatment) were randomized to sites using a Latin square design. The reactions were evaluated clinically and instrumentally.

LIMITATIONS

Study was designed to only detect potent anti-irritants.

CONCLUSION

Glycerol reduced the irritant effect of both sodium lauryl sulfate and NON, whereas triamcinolone acetonide appeared to have beneficial effect only on the irritation induced by NON. The study provided experimental documentation for the claim that glycerol has anti-irritant effect in a cosmetic formulation.