The Influence of Sebum on Directional Reflectance of the Skin

The sebaceous glands are responsible for the secretion of sebum. Its function is to maintain a proper epidermal barrier and participate in metabolic processes within the epidermis. Excessive sebum secretion leads to the development of various seborrheic diseases. The aim of this study was to determine the in vivo correlation between the amount of sebum and the directional reflectance of the skin. Measurements were performed using a Sebumeter (Courage + Khazaka, Germany) and a directional hemispherical reflectometer (Solar 410, SOC, USA). It has been shown that the amount of sebum does not affect the directional reflectance of the skin at a wavelength of 335-380 nm. With an increase in the amount of sebum, the directional reflectance of the skin decreases at wavelengths of 400-540 nm and 480-600 nm. However, with an increase in the amount of sebum, the directional reflectance of the skin increases at wavelengths of 590-720 nm, 700-1100 nm, 1000-1700 nm, and 1700-2500 nm. The closest relationship between amount of sebum and directional reflectance of the skin was observed at a wavelength of 700-1100 nm. Reflecting/scattering radiation from the skin surface, depending on the sebum content, may be clinically significant not only in the context of exposure to solar radiation but also in the context of numerous therapeutic methods based on artificial sources of radiation. In this area, it is desirable for the radiation to penetrate the skin as effectively as possible. The obtained preliminary results confirm that the used method is an interesting alternative to spectroscopic methods.