The clinical significance of cutaneous reactions to trichophytin in dermatophytosis.

An intracutaneous test was performed in 114 patients with dermatophytosis verified by culture and in 32 control subjects, unsing purified trichophytin (according to the ethylene glycol method) and commercially available trichophytin. Immediate reactions occurred with both trichophytin antigens at a similar frequency in 12-14% of cases. Delayed reactions occurred significantly more often to the purified trichophytin in patients with dermatophytosis (36%) but in none of the controls. Immediate reactions to purified trichophytin occurred in 26% of the chronically infected patients. Delayed reactions were correlated to patients with tinea cruris (50% positive reactions), to infections with Epidermophyton floccosum (50%) and to patients not chronically infected. Thus, chronic dermatophytosis was characterized by immediate reactions to purified trichophytin and few delayed reactions. In contrast, patients not chronically infected were characterized by delayed reactions and few immediate reactions.