The effect of oral and topical tetracycline on acne severity and on surface lipid composition.

Groups of 20 males of high-school age with moderate acne were treated with oral tetracycline (500 mg/day), topical tetracycline (0.5% solution applied twice daily), or placebo for 8 weeks. The two panels treated with tetracycline showed a significant and equivalent reduction in acne severity as assessed by visual grading. The surface lipids in the panel treated with oral tetracycline showed a small but not statistically significant decrease in free fatty acid content, but the subjects receiving topical tetracycline showed no reduction in free fatty acids. Further, neither treatment was associated with a change in mass of surface lipid nor did the mass or weight percent of any component of the surface lipids change with the decrease in acne severity. These results show that acne severity can be reduced with tetracycline (both oral and topical) without any concomitant quantitative change in surface lipids.