The present invention provides a liquid formulation for the treatment of a skin condition associated with leukocyte accumulation in the skin, comprising a therapeutic compound selected to reduce leukocyte accumulation in the skin； and an aqueous solution of an organic solvent, wherein the organic solvent increases skin permeability. The present invention also provides a method of treating a skin condition associated with leukocyte accumulation in the skin, comprising the steps of applying topically a liquid formulation of a photosensitizer to a skin lesion of a patient afflicted with the skin condition； and exposing the skin lesion to a light source.
