Biophysical characteristics of healthy skin and nonlesional skin in atopic dermatitis: short-term effects of ultraviolet A and B irradiation.

The present study was designed to evaluate basic differences in surface structure and viscoelastic properties of nonatopic versus atopic skin and facultative acute changes following ultraviolet irradiation. Therefore, biophysical measurements by means of profilometry and cutometry were carried out on sun-protected unaffected gluteal skin areas in both groups before and 24 h after single UVA and UVB irradiations. The results indicate that the clinically unaffected skin of patients with atopic eczema differs from normal skin in terms of increased roughness parameters, but not concerning depth of furrows or viscoelastic properties (viscosity and biological elasticity, cutometrically calculated). Single UVA irradiation with 50 J/cm(2) induced neither measurable changes in the skin's surface structure nor in its viscoelastic properties in both groups after 24 h. However, irradiation with a single erythemogenic dose of 1 MED UVB was followed by a short-term significant increase in the depths of furrows and decrease in biological elasticity in normal and atopic skin, accompanied by an increase in viscosity in normal skin.