Immunity and Cutaneous Sensitization 35 



cultural tests yielded negative results, from 50 to 58 per cent showed a 

 positive reaction to trichopliytin. Iu many of these cases previous treat- 

 ment had masked the infection and made the isolation of fungi difficult. 

 In others the primary disorder was definitely determined to be nonmycotic. 



The test was of little value for this series of patients, except that a doubtful 



TABLE 8.— Reaction to Thichophytin Test of Patients undeh 20 Years, 

 Examination for Fungi Having Given Negative Results 



reaction to trichophytin led us to repeat the cultural studies. Of 106 patients 

 under 20 years of age who had rashes which were not considered fungous, 

 only 15 per cent reacted to the trichophytin test (Table 8). We therefore 

 wish to stress the diagnostic value of a positive reaction to trichophytin in 

 children and young adults. In tests of 45 patients over 50 years of age who 



TABLE 9.— Reaction to Trichophytin Test of Patients over 50 Years, 

 Examination for Fungi Having Given Negative Results 



were clinically free of fungi, 31 to 35 per cent of the reactions were posi- 

 tive (Table 9), over twice the percentage of patients under 20 years. The 

 possibility of error therefore increases with age. In tests of 77 patients of 

 miscellaneous ages with various cutaneous disorders not considered to be 

 mycotic, from 16 to 20 per cent of the reactions were positive (Table 10). 

 In a series of 216 cases in which an eczematous eruption was confined 

 to the hands and in which incidental examinations for fungi on both the 



