Olopatadine Hydrochloride Improves Dermatitis Score and Inhibits Scratch Behavior in NC/Nga Mice

Background: Control of itch is an important issue in the treatment of atopic dermatitis (AD). Itch is mediated by a variety of pruritogens, including histamine, and promoted by neurite outgrowth in the epidermis of AD patients, probably due to the release of nerve growth factor. Objectives: We investigated the effects of orally administered olopatadine hydrochloride (olopatadine) on itching, itching mediators, and neuritogenic action in a mouse model. Materials and Methods: NC/Nga mice were treated topically with Dermatophagoides farinae body (Dfb) extract twice weekly for 4 weeks to induce AD-like lesions. They were concomitantly given oral olopatadine, distilled deionized water, or topical tacrolimus during the last 2 weeks. Results: Olopatadine significantly suppressed scratching, improved the dermatitis score, inhibited neurite outgrowth, and decreased the elevated inflammatory markers, growth factors and histamine content in the lesional skin, and serum concentration of Dfb-specific IgE. Notably, olopatadine treatment increased semaphorin 3A expression in the epidermis. Conclusions: Our study confirms the pleiotropic effects of olopatadine, i.e. inhibition of inflammation and neurite extension into the epidermis. Copyright (C) 2010 S. Karger AG, Basel