Background: Controversy exists as to whether treatment of actinic keratoses with intermittent doses of topical 5-fluorouracil is effective in the absence of significant irritation.
Objective: To evaluate the efficacy and degree of irritation of 5-fluorouracil as a function of its application frequency.
Methods: A total of 85 actinic keratoses in 53 patients were treated, initially with four applications per week for the first week. After this first week, if intolerable irritation arose, patients were instructed to reduce application frequency to two times per week for the rest of the treatment period.
Results: Treatment was completed for 95.4% of the lesions included, with healing of 88.6% of them. The mean time to healing was 7.4 weeks (with four applications weekly) and 10.2 weeks (with two applications). The healing rate was similar in the two groups. Significant correlations (p<0.001) were observed between application frequency and time to healing.
Conclusion: Intermittent 5-fluorouracil treatment is effective without causing significant irritation, but time to healing increases with declining application frequency.