Measurements of the Human Skin: Why and How?

Abstract

Metrology is the science of measurement, of evaluation of its requirements, limitations and interpretations. The primary reason for the use of metrology in non-invasive cutaneous investigations is its role as a major source of progress, not only because impressions are replaced by objective facts and qualitative descriptions by quantitative assessments, but also because new situations are unveiled. Even the simplest phenomenon becomes complex when measured; one starts from one fact and then discovers its possible components and variations, which induces new hypotheses and open a path for new knowledge. Physics in the past could only progress through the development of measurement methods. The remarkable advances in human physiology during the 19^th century, which preceded modern medicine and allowed it to progress, were due to a double process of discovery and quantification. Skin metrology provides many examples. The measurement of sebum “secretion” with a view to correct the removal of lipid from the surface quickly showed that the measured phenomenon was not the one expected, but the partial emptying of a follicular reservoir the existence of which had been previously ignored. The measurement of epidermal turn-over in psoriasis provided a leap forward in understanding the disease.

The last decade of progress in molecular genetics has emphazised the considerable benefit that the collection of data provided by common medical practice might generate, and in years to come practitioners will certainly be involved in such data collection and processing. Such information requires classification substantiation and treatment using statistical parameters. A few non-dermatological specialities also utilize skin measurements; e.g. in physiology (endocrinology, body temperature regulation, immunology, etc...) where the skin is an effector organ readily examined non invasively because of its accessibility. It is also the case for cosmetologic research where innocuousness and efficacy criteria may become visually unattainable because of their subtlety, and require instrumental measurements for assessment.

Pierre Agache: deceased

This chapter was originally published under the ISBN 978-3-540-01771-4. The content has not been changed.