TRICHOPHYTON TONSURANS 



999 



Trichophyton tonsurans Malmsten, 1845. 



Synonyms. — Trichomyces tonsurans Malmsten, 1845 ; Oidmm ton- 

 surans Zopf, 1890 ; Trichophyton megalosporum endothrix Sabouraud, 

 1894; T. crateriforme Bodin, 1902, which is the term in current 

 use in dermatological literature. 



Causes a type of tinea capitis some- 

 what rare in England, but common 

 on the Continent. The hairs are 

 broken 2 to 4 millimetres from the 

 scalp, and the stumps are variously 

 bent. The diseased hairs have a 

 powdery, greyish appearance, and 

 on pulling them out the roots are 

 not black, as in normal hairs. It 

 belongs to the type Endothrix. The 

 mycelial cells are large (4 to 5 

 quadrangular (so-called resistant 

 mycelium type). Grows well on 

 maltose agar and other media; on 

 maltose agar colonies are white or 

 yellowish, often crateriform, and present a velvety surface at 

 first, later powdery. In hanging-drop cultivations spore-bearing 

 fructifications can be seen. 



T. tonsurans, besides producing a type of tinea capitis, produces 

 also a form of tinea corporis and a trichophytosis of the nails. 



Trichophyton sabouraudi R. Blanchard, 1895. 



Synonym. — Trichophyton acuminatum Bodin, 1902. This is the 

 term commonly used in dermatological works. 



This Trichophyton is of the type Endothrix. Mycelial threads 

 have a moniliform appearance, and their articles become easily 

 dissociated (so-called fragile mycelium). Grows well on maltose 

 agar, giving rise to conical white colonies; often acuminate with 

 central plumes, and occasionally may present yellowish or pinkish 

 rings; older cultures may present a powdery surface of a dark 

 pinkish colour. Pleomorphism always absent. In hanging-drop 

 cultures aerial filaments with lateral conidia are seen. 



T. sabouraudi causes a form of tinea capitis called by Sabouraud 

 ' tondante peladoide,' and also a variety of tinea circinata. 



The tinea capitis induced by this fungus is also known under the 

 name of 'black-dotted ringworm.' The hairs get broken lower 

 than in the type of ringworm caused by T. tonsurans. The stumps 

 are on the same level as the surface of the scalp, and appear as 

 black dots. 



Trichophyton pilosum Sabouraud, 1909. 



Very similar to T. sabouraudi, from which it differs only by the 

 cultures being covered, when old, by a dense, short, white duvet. 



Fig. 505. — Trichophyton tonsu- 

 rans Malmsten. 



(Preparation of a hair in liquor 

 potassse, after Sabouraud.) 



