A new standardized method of evaluating cutaneous irritation from topical medications

We used a new technique to evaluate and compare cutaneous irritation from various topical medications. Twenty participants with corticosteroid-responsive dermatoses were enrolled. Three target areas of unaffected skin were abraded. A negative control (petrolatum ointment), a positive control (an over-the-counter [OTC] anti-itch preparation containing benzyl alcohol), and a test product (fluticasone propionate lotion 0.05%) were each applied to separate targetareas on the legs. Participants rated the irritation of each target area using a 10-point scale (1 [no symptoms] to 10 [intolerable burning/ stinging requiring removal of the medication]). The mean irritation scores for petrolatum ointment, the OTC anti-itch preparation, and fluticasone propionate lotion 0.05% were 1.20, 6.15, and 2.05, respectively. The difference in irritation between the OTC anti-itch preparation and fluticasone propionate lotion 0.05% was highly significant (P < .0001). The difference in irritation between the OTC anti-itch preparation and petrolatum ointment also was highly significant (P < .0001). The difference in irritation between fluticasone propionate lotion 0.05% and petrolatum ointment also was statistically significant (P = .0104). Irritation scores were then standardized on a 10-point scale, with the irritation score of the negative control given a value of 1.00 and the irritation score of the positive control given a value of 10.00. The standardized irritation score of the test product, fluticasone propionate lotion 0.05%, was calculated to be 2.55. Our assay was able to detect and quantify even minimal cutaneous irritation secondary to application of topical medications.