A case is presented which illustrates in an unusual manner and ability of topically applied fluorouracil (FU) to selectively destroy actinic keratoses without harm to normal skin. This is demonstrated by comparing the effect of the drug on facial skin which was severely damaged by actinic radiation and extensively involved with actinic keratoses, and the effect upon adjacent uninvolved skin grafted to the face from the thigh. The actinically damaged skin reacted to the drug with the expected inflammatory reaction whereas the grafted skin did not.
Saltzer EI, Soderquist NA, Wilson JW. Selectivity of Fluorouracil in Treatment of Actinic Keratoses. Arch Dermatol. 1968;98(2):166-167. doi:10.1001/archderm.1968.01610140064015