314 An Introduction to Medical Mycology 



(a) Clinical characteristics.— Tinea versicolor is a superficial scaly 

 eruption with yellowish to brown color, favoring the trunk and usually 

 seen in young adults. Fluorescence may be noted when the rash is exam- 

 ined under filtered ultraviolet radiation. An interesting feature is the fre- 

 quent appearance of pseudo-achromia at the site of the eruption after inju- 

 dicious exposure to solar radiation. 



(b) Immunologic reactions.— No sensitization of the skin has been dem- 

 onstrated. 



(c) Microscopic features. — The facility of diagnosis is rarely ap- 

 proached even occasionally with specimens from any other mycosis. The 

 scales may be examined as soon as the potash preparation is made. There 

 is usually an abundance of material consisting of spherical or ovoid re- 

 tractile spores in groups or clusters. Mycelium is seen in considerable num- 

 bers as wavy threads of moderate length. Branching may be noted. The 

 filaments are readily broken up when one is making the mount. When scales 

 are removed from the surface of patches of pseudo-achromia, only a few 

 spores, without appreciable grouping, may be noted. Filaments are usually 

 few; they consist of short rods. 



(d) Cultural characteristics.— A number of investigators have re- 

 ported success in culturing the organism, but so far there is no general 

 agreement. Moore described experiments in which he obtained cultural 

 growths on many different mediums after the initial isolation on maltose 

 broth. He was able to inoculate three of eight human volunteers when no 

 laboratory animal was susceptible. In addition to proving with the usual 

 evidence that a given culture is pathogenic for animals or for human volun- 

 teers, it appears essential to note fluorescence under filtered ultraviolet 

 rays, of the cultural growth and of the lesion experimentally produced, since 

 fluorescence is characteristic of M. furfur. This observation has not yet been 

 reported. 



(e) Filtered ultraviolet rays.— The rash caused by M. furfur fluoresces 

 either a light or a dark brown according to the degree of pigmenta- 

 tion present. The usual color is golden yellow. The appearance of the cul- 

 tural growth is unknown. 



(f ) Animal inoculation.— Ordinary laboratory animals appear immune 

 to the fungus applied in scales. Cultural growths would be essential to a 

 definite decision of this point. 



(g) Differential diagnosis.— The presence of clusters of spores (appar- 

 ently with double-contoured walls) and of fragmented mycelium (usually 

 abundant) provides a characteristic picture. In M. albicans the filaments 

 arc more slender and dense masses of spores ( sometimes budding) are a dis- 

 tinguishing feature. 



