Expression of a messenger RNA which encodes a protein which is expressed by differentiated cells, notably the cells of the skin or appendages thereof, is inhibited by topically administering to said differentiated cells a thus effective amount of at least one double-stranded RNA oligonucleotide, formulated into a topically applicable, physiologically acceptable medium therefor; such regime or regimen is useful for treating a variety of afflictions or conditions, e.g., combating the signs of skin aging, stimulating hair growth or retarding loss thereof, inhibiting cellular proliferation and/or differentiation, etc.