An ulcer is a crater-like sore on the skin or mucous membrane. Ulcers form when the top layers of skin or tissue have been removed. They can occur in the mouth, stomach, and other parts of the body.
Ulcers can be caused by inflammation or infection. Some ulcers may be caused by a cancer.
Armstrong CA. Examination of the skin and approach to diagnosing skin diseases. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 444.
Habif TM. Principles of diagnosis and anatomy. In: Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, PA: Elsevier Mosby; 2009:chap 1.
Update Date 12/2/2014
Updated by: Richard J. Moskowitz, MD, dermatologist in private practice, Mineola, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.