Examination of the Epidermis by the Strip Method of Removing Horny Layers

Abstract

Some years ago, Wolf (1) developed a new method of examining the surface relief of the skin by stripping off the most superficial horny layer by means of transparent adhesive tape. He demonstrated that a one-layered sheet of horny cells will stick to the tape which then can be mounted on a glass slide and examined at any desired magnification. It occurred to me that Wolf's method might be valuable in many other ways for gaining more information not only about the horny layer, but about the entire epidermis. Two applications of the strip method are presented in this preliminary communication. A. Thickness of the Horny Layer It is not difficult to count the number of layers of the rete mucosum by counting the nuclei in the usual perpendicular sections. But it is almost impossible to count or even to estimate the number of horny layers. It was found that ordinary Scotch Tape ® is well suited for the performance of the strip method. A strip 1.25 cm (inch) wide and about 5 cm long was applied to the flexor surface of the forearm, rubbed lightly to assure adhesion, and then stripped off with a quick movement. For this purpose one end was grasped and the tape was rolled back on itself. It was then applied, sticky side down, to a clean microslide and examined under the microscope. Wolf's observation was borne out. A single sheet of horny cells adhered to the tape, and the various details of surface relief described by him could be studied easily. The sheet of cells was not quite complete , but an estimated two thirds of the skin surface had been stripped off. The surface of the treated skin did not differ appreciably from the surroundings. A second strip of scotch tape was applied and removed and showed a very similar picture under the microscope. The procedure was then repeated over and over with the intention of stripping off as many layers as possible. After four or five applications, the surface looked slightly more dull than the surroundings, but it was not until 24 strips had been applied and pulled off that a definite change was seen. Small shiny reddish areas of irregular size and shape appeared, continued to increase in number with each application, and became coalescent. At the same time, a slight burning sensation was perceived. The cells which adhered to the tape became more single and few in number, but no nuclei or keratohyalin