An ulcer represents a localized break in the protective barrier of a body tissue, occurring on the skin or an internal mucous membrane. This breach results from the disintegration of the surface epithelial tissue, creating an open sore. Because protective linings vary significantly, the location of an ulcer often dictates its specific cause, characteristic symptoms, and necessary treatment approach.
Ulcers of the Upper Gastrointestinal Tract
The upper digestive tract (esophagus, stomach, and duodenum) is a common site for ulcers collectively known as peptic ulcers. These sores form when the mucosal lining fails to withstand the erosive action of stomach acid and digestive enzymes. The most frequent culprits compromising this defense are infection with the bacterium Helicobacter pylori and the long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs).
A Gastric ulcer occurs directly in the lining of the stomach, and the pain often worsens immediately after eating. Conversely, a Duodenal ulcer forms in the duodenum, the first segment of the small intestine. Pain from a duodenal ulcer often presents when the stomach is empty, such as between meals or at night, and may feel temporarily relieved by eating food that buffers the acid.
Esophageal ulcers develop in the lining of the muscular tube connecting the throat to the stomach. They are most commonly caused by chronic exposure to stomach acid backing up from the stomach, known as gastroesophageal reflux disease (GERD). Certain medications, such as some antibiotics or osteoporosis treatments, can also irritate the esophageal lining if they become lodged in the tube, leading to a localized ulcer.
The symptoms of an esophageal ulcer often include painful swallowing or a burning sensation felt behind or beneath the breastbone. The precise location determines the specific timing and nature of the pain experienced. The presence of blood in vomit or dark, tarry stools can signal a serious complication from a bleeding ulcer in this region.
Ulcers of the Oral Cavity and Lower Intestines
Ulceration can affect the oral cavity, most commonly presenting as aphthous ulcers, better known as canker sores. These small, shallow lesions typically develop on the soft, non-keratinized tissues inside the mouth, such as the inner surfaces of the cheeks, lips, tongue, or soft palate. Unlike viral cold sores, aphthous ulcers are not contagious and are not related to acid erosion.
The formation of these oral ulcers is often linked to localized trauma (like an accidental cheek bite or aggressive brushing), emotional stress, or specific nutritional deficiencies (including low levels of iron or B-vitamins). They usually appear with a white or yellow center surrounded by a distinct red border and can cause significant pain, particularly during eating or talking.
Moving further down the gastrointestinal tract, the lower intestines are a site for ulcers associated with systemic inflammatory conditions. Colonic ulcers, which occur in the large intestine and rectum, are a defining feature of inflammatory bowel diseases (IBD). Ulcerative Colitis, one of the two main forms of IBD, causes inflammation and shallow ulcers typically confined to the colon and rectum, often starting in the rectum and extending upward.
The other major IBD, Crohn’s disease, can cause ulcers anywhere along the digestive tract, from the mouth to the anus, but it most commonly affects the small intestine and the upper part of the large intestine. Unlike the superficial ulcers of Ulcerative Colitis, Crohn’s ulcers are often deeper, penetrating through the thickness of the bowel wall in a patchy pattern. These lower intestinal ulcers signal a problem with the immune system mistakenly attacking the body’s own tissue.
Ulcers of the Skin and Extremities
Ulcers that occur on the skin and extremities are distinct from digestive issues, primarily arising from problems with circulation or prolonged pressure. Venous ulcers, the most common type of leg ulcer, typically form on the lower leg, particularly just above the ankle. They result from chronic venous insufficiency, where malfunctioning valves cause blood to pool in the lower limbs, leading to sustained high pressure that damages the skin tissue.
Arterial ulcers, conversely, occur due to a lack of oxygenated blood supply, often caused by atherosclerotic disease in the arteries. These wounds usually appear on the feet, toes, heels, or other bony prominences of the lower leg. They often have a characteristic “punched out” appearance with well-defined edges. The severe lack of blood flow makes arterial ulcers acutely painful, with the pain often worsening when the leg is elevated.
A third major category is the pressure ulcer, also known as a bedsore or decubitus ulcer, which forms over areas of bone close to the skin surface. These lesions are most common in individuals with limited mobility, developing over the sacrum (tailbone), heels, hips, and ischial tuberosities (sitting bones). Sustained mechanical pressure in these areas compresses the soft tissue between the bone and an external surface, such as a bed or wheelchair. This compression restricts blood flow and causes localized tissue death.