Acne occurs when the openings of hair follicles become clogged and blocked with oil and dead skin cells. If the clogged pore becomes infected with bacteria, it forms a pimple, which is small red bump with pus at its tip.
Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.
Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press.
Make your tax-deductible gift and be a part of the cutting-edge research and care that's changing medicine.