Chitosan-based nail formulations are useful to treat nail inflammatory diseaseslike psoriasis, atopic dermatitis and lichen planus. The chitosan is normallyin the form of an amino-polysaccharide derivative, preferably water soluble,such as hydroxypropyl chitosan. The formulation may be a nail lacquer, a spray,a cream, an ointment, a gel, a lotion or a foam and may have a content in chitosan,chitosan derivative or a salt thereof from 0.1 to 25 wt.% with respect to the totalweight of the formulation.
