Topical herbal extract (Huangdang mixture) exhibits both preventive and therapeutic effects in murine acute irritant contact dermatitis

Background Contact dermatitises, including allergic contact dermatitis and irritant contact dermatitis, are among the most common skin disorders in humans. Chinese herbal medicines (CHM) have been used in treating contact dermatitises for centuries. Systemic administration of CHM, including ingredients in Huangdang mixture containing Chinese angelica, Radix Paeonlae rubra, cat nut, and phelloden dron, rhizoma alismatis, rhizoma smilacis glabrae, and rhizome of swordlike, improves allergic contact dermatitis induced by l-fluoro-2,4-dinitrobenzene. Whether topical applications of these herbal extracts display preventive and/or therapeutic effects on contact dermatitis, thereby avoiding the potential side effects of systemic CHM, remains largely unknown. Aims To determine whether this topical CHM extract exerts preventive and/ or therapeutic effects, we assessed its efficacy in both allergic contact dermatitis and irritant contact dermatitis murine models. Materials and methods Allergic contact dermatitis and irritant contact dermatitis murine models were established by topical oxazolone and a phorbol ester (12-O-tetradecanoylphorbol-13-acetate; TPA), respectively. Ear thickness was assessed in both dermatitis models. Results Our results demonstrate that this topical CHM extract exhibits both therapeutic and preventive effects in acute irritant contact dermatitis but no demonstrable efficacy in murine allergic contact dermatitis. Conclusion These results suggest that this topical CHM extract could provide an alternative regimen for the prevention and treatment of irritant contact dermatitis.