Abstract
The scalps of 40 adults and 10 children without tinea capitis, which included 16 patients with tinea corporis due to Microsporum canis, and 34 family members were examined using the hairbrush method. In addition, 8 patients with tinea capitis and 21 pet cats which were sources of infection in the same homes were also investigated. The results were as follows: 1) M. canis was isolated in 32 of the 50 cases (64%) who had no scalp lesions. 2) Positive rates and number of colonies correlated with the source of infection within homes, i. e., many cats, one cat or a tinea capitis patient, in that order. The dermatophyte was not detected in families only with a patient with tinea corporis and without cats. 3) when the source of infection was treated simultaneously, scalp lesions did not develop in any of the adults. However, one case of tinea capitis developed in a three-year-old boy. 4) Positive rate and number of colonies were shown to decrease after hairwash. 5) Positive rate and number of colonies correlated with the results of the hairbrush method on the source of infection.
From the above findings we can infer that in most cases the dermatophyte exists only as a saprophyte. Moreover, if the source of infection is being addressed, we believe it is unnecessary to treat adult cases without scalp lesions. Prophylactic treatment in children may, however be necessary or advisable.
