1. ¹Department of Dermatology, University of Oregon Medical School, Portland, Oregon
2. ²The Mason Clinic, 1118 Ninth Ave., Seattle, Washington 98101

Received 7 December 1970; Accepted 15 March 1971.

Abstract

The free fatty acids (FFA) of human surface lipids have been implicated by indirect evidence in the pathogenesis of acne vulgaris, and a previous study defined the greater irritancy or penetration of the C₈ to C₁₄ fatty acids. In the present analysis, done by another method, these differing degrees of irritancy were confirmed statistically, and a comparative study of FFA irritancy was done in patients with and without acne.

The even numbered free fatty acids from C₂ to C₁₆ were applied daily under occlusive patch tests to human skin until detectable erythema appeared. C₈, C₁₀ and C₁₂ were found to be significantly more irritating than C₁₄, which, in turn, was significantly more irritating than the group C₂, C₄ and C₆, C₁₆ fatty acid was non-irritating.

The comparison of sensitivity between the skin of patients with acne and those without acne to the irritant effects of FFA revealed no significant differences. The immediate response of both groups to C₈, C₁₀ and C₁₂ acids failed to define whether a significant difference might exist for these highly irritating chain lengths. The similarities in response of both groups to the other chain lengths suggest, however, that the skin of the patient with acne is no more sensitive to irritant FFA than normal skin. Although the conditions of the study did not reproduce the pathophysiologic state in the follicle in acne, we believe that these data exclude the alternative that the skin of the patient with acne is more sensitive to the irritant effects of FFA than the skin of patients without acne.