The invention provides a compound of formula (I)wherein:A, B, C, D, W, X, Y and Z are each independently selected from H and OH；or a salt thereof；for use in the treatment and/or prevention of a skin condition in a subject, wherein the compound of formula (I) or salt thereof is administered topically. The invention further provides topical compositions of a compound of formula (i) and processes for the preparation of said compositions.
