ulcer

ulcer An erosion of an epithelial surface — the skin, or any of the internal linings (mucous membranes) that are in continuity with the skin at the body orifices. Damage may be physical, chemical, due to failure of blood supply or to infection. Peptic ulcer may be gastric or duodenal — affecting the mucous membrane of the stomach or of the duodenum, attributed to the effects of stomach acid, either when it is in excess, or when the normal defences against damage from it are lacking; now known to be linked with infection by Helicobacter pylori. Oesophageal ulcer is related to reflux of stomach contents. Underlying blood vessels can be eroded, with consequences that can be either insidious, or catastrophic in the case of peptic ulcers; bleeding is readily evident if blood is vomited (haematemesis), but less immediately so if it moves on down the gut to appear (in an altered state) in the faeces (melaena). Less dramatic bleeding can be detected by a test for occult blood in the stool. At worst erosion may penetrate right through the wall — most commonly of the duodenum — causing a perforated ulcer, and escape of gut contents leads to peritonitis.

Ulceration of the skin can occur on the legs as a complication of varicose veins, or of poor circulation due to arteriosclerosis. Bedsores are ulcers caused by prolonged pressure and immobility. Some types of skin cancers or other skin diseases can form ulcers. Aphthous ulcers are small painful erosions of the mucous membrane in the mouth. Without the protection of an intact surface, ulcers from any cause can become deeper due to injury or infection.

Sheila Jennett