Influence of age and sun exposure on the biophysical properties of the human skin: an in vivo study.

The physical properties of the skin were measured by using noninvasive methods on 72 people displaying various levels of solar elastosis on the neck. The physical parameters measured were the skin extensibility, the elastic recovery, the skin colour, the skin thickness and the electrical conductance. The correlation between the above parameters, the clinical grades of elastosis and the chronological age of each subject were studied using two different statistical approaches. They both showed that elastotic skin is less elastic, dryer, darker, more erythematous and less yellowish than the nonexposed skin. The similarities and differences between the properties of elastotic skin and purely chronologically aged skin are discussed.