Comparative in-vivo activity of clotrimazole and a clotrimazole/hydrocortisone combination in the treatment of experimental dermatophytosis in guinea pigs.

To compare the activity of clotrimazole with a clotrimazole/hydrocortisone combination, guinea pigs were infected with Trichophyton mentagrophytes var. mentagrophytes. The animals were treated with once daily application of clotrimazole alone, hydrocortisone alone, base alone or a combination of clotrimazole and hydrocortisone. One group of animals was left untreated. Daily clinical observations were made. At intervals during the three week study animals were killed, skin scrapings were taken for microscopical examination and culture and skin was removed for histological examination. The responses of the guinea pigs treated with the base alone reflected those of the untreated controls. They were mycologically positive throughout the study and showed extensive inflammatory reactions on histology. Animals treated with hydrocortisone alone rapidly developed a severe clinical infection and mycological examination was positive throughout. Animals treated with clotrimazole alone did not show severe clinical reactions and were negative on culture after four treatments; histology showed inflammatory scabs after resolution of infection. Clinically, the animals receiving combination therapy improved most quickly and cultures were negative after two treatments. Histological examination showed resolution of the infection and little inflammation.