Leukopenia usually follows every course of adequate therapy with fluorouracil.
The lowest white blood cell counts are commonly observed between the 9th and 14th days after the first course of treatment , although uncommonly the maximal depression may be delayed for as long as 20 days. By the 30th day the count has usually returned to the normal range. Alopecia and dermatitis may be seen in a substantial number of cases. The dermatitis most often seen is a pruritic maculopapular rash usually appearing on the extremities and less frequently on the trunk. It is generally reversible and usually responsive to symptomatic treatment.