102 Ajj Introduction to Medical Mycology 



per cent of those infected with T. purpureum have a positive reaction after 

 48 hours. With the latter infection an immediate wheal reaction to trichoph- 

 ytin may be expected in about 40 per cent of patients. With the acute 

 form of ungual involvement due to T. gvpseum, there may be initiation of 

 cutaneous sensitivity, as evidenced by the development of a reaction to 

 trichophytin. The superficial type (leukonychia trichophytica ) and the in- 

 fections due to T. purpureum seldom have the ability to sensitize. The 

 same is true of ungual infections due to A. schoenleini. 



(e) Clinical characteristics.— There are two chief forms of the dis- 

 order, namely, (1) the inflammatory type, due to T. gypseum, and (2) 

 the chronic type, due to T. purpureum. Since there is a wide difference in 

 the appearance, behavior and response to treatment of each, they will be 

 taken up separately. 



(1) Inflammatory type {Trichophyton gypseum). 



a. Involvement of the skin. The disease commonly makes its appearance 

 on the feet in the form of vesicles on an interdigital web, on the sole or 

 on both. 



In the first-mentioned location the vesicles, or bullae, rupture readily, 

 and the skin at the site of the lesion becomes macerated and soggy. The 

 process is usually associated with a certain degree of erythema, but this 

 may be lacking. The condition may remain in this stage for weeks, months 

 or years. On examination some maceration and peeling may be noted. The 

 development of fissures or cracks is common. For some reason not yet 

 known the web between the fourth and the fifth toe is particularly vulner- 

 able. In this stage the inflammatory form may be indistinguishable from 

 the chronic type ( due to T. purpureum ) . 



With favorable conditions the disease may assume a more inflammatory 

 character. This usually occurs during the summer season, although not 

 exclusively. The first indication may be pruritus of the toes accompanied 

 by some swelling (edema) and followed by appearance of vesicles. The 

 soles may be the chief areas affected, but if the inflammation is violent, 

 vesicles may appear on the sides of the toes and feet. Owing to scratching 

 and trauma from local applications (self-medication being exceedingly 

 common) there is an increase in the inflammatory reaction, and secondary 

 pyogenic infection may appear. Coincidentally with the increase in the lo- 

 cal inflammation on the feet and frequently with the development of lesions 

 on the soles, vesicles may appear at a site or sites remote from the original 

 infection. The hands (particularly the palms and sides of the fingers) are 

 chiefly affected. This type of eruption is due to the dissemination of products 

 of fungi through the blood stream, and the lesions are known as der- 

 matophytids. This Subject is considered in more detail on pages 116 to 119. 



