CUTANEOUS REACTIONS IN OTHER MYCOSES 135 



after the lesions have healed; and that some individuals, even those 

 in whom a previous history of ringworm cannot be established, may 

 react; so that, as with tuberculin, a negative reaction is of more 

 diagnostic value than a positive one. Trichophytin is claimed by 

 some to have some therapeutic value in certain deep-seated infec- 

 tions, but the effect is not a specific one. There occurs a focal re- 

 action in the lesion as well as the local one at the site of inoculation, 

 and such therapeutic effect as is noted is to be attributed to this in- 

 creased inflammatory reaction, which is no greater than that ob- 

 tained when irritants are applied locally. The trichophytins have 

 been prepared in various ways. According to Bloch, the best pro- 

 cedure is to evaporate the broth filtrate to one-twelfth its original 

 volume, to which is added the cell sap expressed from the mycelium. 

 The active substance has been chemically investigated by Bloch, 

 Labouchere, and Schaaf,^ who claim that it is a starch-like, nitrogen- 

 containing, levorotatory polysaccharide. 



Trichophytid. In connection with the allergic reactions of ring- 

 worms, mention should be made of the condition known as tricho- 

 phytid, first described by Jadassohn. This is a generalized skin 

 eruption occurring during the course of a ringworm infection, similar 

 to the generalized eruptions occurring in scrofula or other forms of 

 tuberculosis, and designated tuberculide by Darier. It is as yet un- 

 certain whether this affection is due to a toxic reaction of some sort 

 (perhaps caused by an allergic state of the patient) or to a dis- 

 semination of the fungus by the blood stream. The former hypothesis 

 seems more reasonable, but positive blood cultures have been re- 

 ported. Experimental trichophytid in the guinea pig has been de- 

 scribed."*' 



Cutaneous Reactions in Other Mycoses. The cutaneous reactions 

 in coccidioidomycosis have been studied more thoroughly than in 

 other mycoses. Dr. C. E. Smith has prepared most of the coccid- 

 ioidin used in skin testing and has had a very extensive experience 

 in its use. He prepares the material by growing strains of Coccid- 

 ioides immitis on a synthetic broth medium like the medium used in 

 the preparation of old tuberculin except that there is a reduction in 

 the amount of glycerin. The composition of the medium and the 

 method of preparation and use are outlined in the section on coccid- 

 ioidomycosis. 



Coccidioidin appears to be highly specific, but some lots give non- 

 specific reactions and have to be discarded. A small number of per- 

 sons who have had no recognized exposure to Coccidioides react to 



