An infection of the topmost layers of the skin, especially one caused by staphylococci, may produce pustules, which look like small blisters containing a thick, yellowish material.
Review Date 10/8/2018
Updated by: Linda J. Vorvick, MD, Clinical Associate Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.