The efficacy of griseofulvin administered to prevent experimentally induced inflammatory dermatophytosis was assessed in a randomized, double-blind trial involving six drug-treated and six placebo-treated subjects. Volunteers were challenged with a standard inoculum of spores from a zoophilic (granular) strain of Trichophyton mentagrophytes. One-gram doses of micronized griseofulvin daily provided significant protection against the development of florid inflammatory lesions (P<.01), but did not prevent minimal signs of infection from appearing in five of six drug-treated subjects. No lesions developed where heatkilled spores had been placed. Serial cultures of the ankle challenge sites were positive seven times less often in the griseofulvin-treated subjects than in the controls (P<.001). After stopping medication, inflammatory lesions developed in three of the drug-treated subjects, but in none of the placebo-treated subjects.
Allen AM, Reinhardt JH, Akers WA, Gunnison D. Griseofulvin in the Prevention of Experimental Human Dermatophytosis. Arch Dermatol. 1973;108(2):233-236. doi:10.1001/archderm.1973.01620230033012