The Use of Cellophane Tape in the Diagnosis of Tinea Versicolor

Abstract

For the last three months Scotch Tape has been used to demonstrate the presence of Malassezia furfur in scales removed from lesions of Tinea versicolor. Nine patients with typical manifestations of the disease were used for this study. METHOD The face or sticky side of a one inch wide piece of Scotch Tape is applied to the suspected lesion, gently pressed down, immediately removed and pressed on a clean, oil free microscope slide. By repeating this procedure on the same lesion clearer and thinner specimens are obtained. If the lesions are small and discrete, the scales adhere in such a way that they seem to be transported to the tape and there is no difficulty in locating the right area for microscopic examination. This feature is rather striking when follicular lesions are examined. MICROSCOPIC EXAMINATION The fungus may be easily recognized, even under low power magnification. In subdued light, collections of small, grouped, round spores are easily seen among the epidermal cells. Under high dry magnification with subdued light, the spores are seen as single, walled, clustered bodies in a grape-like arrangement. With brighter illumination they appear as small, round, single walled structures. Occasionally, one may see hypha-like structures arising from such spores, (Fig. 1), and some clusters of spores seem to be surrounded by a sac-like covering giving the impression of asci. Scattered throughout the field are a large number of hyphae (Fig. 2). They may be discrete or matted together, forming a dense mycelium. The number of hyphae seems to decrease as deeper specimens are taken from the same lesion. These hyphae appear longer and more numerous than those seen in KOH preparations. In some hyphae one may see budding-like organs at one end, but it could not be determined whether the hyphae actually give rise to such structures. In a preparation from one patient there seemed to be a predominance of hyphae which were not as bent or curved as those seen in preparations from the other cases. In all of them, however, branching, non septate hyphae were observed. Despite the fact that different clinical variants of the disease were studied, no significant differences were noted in the appearance of the structures of the fungus. ARTEFACTS Although artefacts due to the glue of the tape and possibly to the oils of the skin are found, no real difficulty was apparent in identifying the fungus. One may see hypha-like structures and spore-like clusters. The former, however, show no branching and the latter have a honeycomb appearance which under subdued light appear as empty spaces without the double walled contour. 229 230 THE JOURNAL OF INVESTIGATIVE DERMATOLOGY COMMENT The Scotch Tape method applied to dry, hyperkeratotic lesions of the hands and feet, in three patients with Trichophyton rubrum infection failed to show the organism, even after repeated trials. However, in one instance, hyphae were seen in a preparation from one lesion of tinea corporis due to T. mentagrophytes and confirmed by a KOH suspension and culture. In three cases of Erythrasma a very fine network of hypha-like structures were seen, but no definite conclusions were reached as to the presence of actual hyphae. Painting the lesions with a solution of Methylene blue or Lactophenol cotton blue failed to help in identifying Nocardia minutissimum. CELLOPHANE TAPE IN TINEA VERSICOLOR 231 SUMMARY AND CONCLUSIONS 1. A simple method for the identification of M. furfur is reported. 2. It is possible to study the spores and hyphae of M. furfur with a minimum of distortion when compared with the KOH method. 3. In the nine patients studied with Tinea versicolor no actual difference in the morphology of the fungus was seen, despite the fact that several clinical variants were observed. 4. The Scotch Tape method seems to be of little use in cases of dermatophytosis and erythrasma. 5. Artefacts are relatively easy to distinguish from the actual hyphae and spores. 6. Scotch Tape preparations can be kept for long periods of time, which makes the method a valuable one for teaching the characteristics of the fungus.