Allergic contact dermatitis from topical fluorouracil.

An allergic contact dermatitis from fluorouracil developed in two patients 8 and 18 days respectively after institution of topical fluorouracil therapy. The character of the usual irritant dermatitis changed to that of an allergic dermatitis. Epicutaneous patch tests and intradermal tests with fluorourcil were reactive. Histologic specimens of positive test sites revealed the changes expected in allergic contact dermatitis. Twelve control subjects failed to react to intradermal fluorouracil tests.