Effects of metronidazole and tinidazole ointments on models for inflammatory dermatitis in mice.

We investigated the effects of 1-4% ointments of metronidazole and tinidazole (derivatives of nitroimidazole) on models of inflammatory dermatitis evoked by antigen, hapten and monoclonal anti-dinitrophenol (DNP) IgE antibody in mice. Metronidazole and tinidazole ointments (1) suppressed the late-phase reaction (LPR) of biphasic ear edema in mice sensitized with ovalbumin (OA), (2) suppressed trinitrochlorobenzene-induced inflammatory dermatitis, (3) suppressed the immediate phase reactions and LPR in mice passively sensitized with anti-DNP IgE mAb, and (4) enhanced vascular permeability and the number of scratching reactions, presumably due to itching, in passively sensitized mice. These results strongly indicate that metronidazole and tinidazole 1-4% ointments possess antiinflammatory, immunosuppressive and anti-itching effects, and have the potential for clinical use in the treatment of human inflammatory skin diseases including atopic dermatitis in addition to rosacea and acne vulgaris.