172 An Introduction to Medical Mycology 



Hairs on which the nodosities form may become triable but are otherwise 

 unchanged. Weidman cultured a species of Actinomyces from a hairy black 

 tongue. When the fungus was fed to a monkey, lesions of trichomycosis 

 developed on the hair of the face and of the axillae. 



(c) Diagnosis.— This is usually indicated by the clinical appearance. The 

 concretions, or nodes, exhibit fluorescence under filtered ultraviolet rays. 

 If a hair to which the concretions are attached is examined under a micro- 

 scope, the mass is seen to be present along a portion of the hair and nits 

 can be excluded from consideration. In our experience, microscopic and 

 cultural examinations have been fruitless so far as the demonstration of 

 fungi has been concerned. Special mediums are necessary, such as those 

 used in isolating Actinomyces bovis. 



(d) Treatment.— The daily use of 10 per cent xylene in petrolatum 

 sometimes dissolves the concretions. Shaving the part is the fastest and 

 surest cure. Recurrence is common. Scrupulous cleanliness is essential to 

 prevent recurrence. 



BIBLIOGRAPHY 



Castellani, A.: Fungi and fungous diseases, Arch. Dermat. & Syph. 16:383, 1927. 



, and Wilkinson, A. G. : Observations on trichomycosis axillaris rlava, rubra and nigra, 



Brit. J. Dermat. 34:255, 1922. 

 Huang, P.: Untersuchung iiber die Erreger von Lepothrix Wilson (Trichomycosis palmcllina, 



Pick), Arch. f. Dermat. u. Syph. 168:235, 1933. 

 Lane, J. E.: Lepothrix, ]. Cutan. Dis. 37:387, 1919. 

 Sibley, W. K., and Muende, I.: Notes on case of trichomycosis axillaris rubra, Brit. J. Dermat. 



43:88, 1931. 

 Weidman, F. D.: Affinities between black tongue and trichomycosis, Arch. Dermat. & Syph. 



18:647, 1928. 



12. TINEA NODOSA (PIEDRA) 



According to McCarthy, two varieties of this disorder exist: (1) the 

 Colombian (South American) type, and (2) the European and Asiatic 

 variety. In both, the disease is manifested by small, hard nodes along the 

 involved hair shaft. We have not observed this disease in New York. 



(a) Etiology.— The disease is said to develop in individuals who wash 

 their hair in stagnant river water and then apply a sticky hair dressing. 

 Two fungi, Trichosporum (Piedraia) hortai and Trichosporum giganteum, 

 are causative. The first-named micro-organism may be isolated from black 

 nodes, whereas the latter is credited as the etiologie agent in the so-called 

 "white" variety in which the nodes are light brown. The infective agent 

 may be demonstrated by mounting the hair with nodes attached in potash 

 solution. The hair is said not to lie affected in any way. According to Mc- 

 Carthy, the nodes are made up of a large number of closely packed cells. 



