This invention relates to a dermatological composition comprising, as an active ingredient, bacteria of at least one Stenotrophomonas strain and/or at least one Stenotrophomonas growth inducer, and the use thereof in the prevention and/or treatment of atopic dermatitis. This invention also relates to an in vitro method for prognosis and/or diagnosis of atopic dermatitis and a method for selecting a Stenotrophomonas growth inducer.