A stricture is an abnormal narrowing of a tube or passageway inside your body. It can develop in the esophagus, intestines, bile ducts, urethra, or other hollow structures, and it restricts the normal flow of food, urine, bile, or other substances. Strictures form when the inner lining of a passage gets damaged, triggering inflammation that eventually produces scar tissue and narrows the opening.
How Strictures Form
The basic process is the same regardless of location. Something injures the inner lining of a body passage: stomach acid washing up repeatedly, an infection, a surgical instrument, or trauma. That injury triggers inflammation. If the damage happens once and heals cleanly, no stricture develops. But when the injury is chronic or severe, the body lays down scar tissue (fibrosis) in the walls of the passage. Over time, that scar tissue thickens and contracts, pulling the walls inward and shrinking the opening.
The passage also loses its natural flexibility. A healthy esophagus or urethra can stretch and contract as material moves through it. A strictured segment becomes stiff, so even a mild narrowing can cause noticeable symptoms because the tissue can no longer expand to accommodate what’s passing through.
Stricture vs. Stenosis
You’ll sometimes see “stenosis” and “stricture” used interchangeably, and they do mean the same thing: abnormal narrowing. In practice, doctors tend to use each term for different body systems. Stenosis typically describes narrowing of blood vessels, heart valves, or the spinal canal. Stricture is more common when referring to the digestive tract, urinary tract, or reproductive system. The underlying concept is identical.
Common Types and Their Causes
Esophageal Strictures
The esophagus is one of the most common sites. Long-standing acid reflux (GERD) is the leading cause: stomach acid repeatedly damages the lower esophagus, setting off a cycle of inflammation and scarring. Eosinophilic esophagitis, an allergic condition that inflames the esophageal lining, can also produce strictures. Less commonly, radiation therapy to the chest, swallowing caustic substances, or certain medications contribute. The hallmark symptom is progressive difficulty swallowing, starting with solid foods and eventually affecting liquids as the narrowing worsens.
Intestinal Strictures
Crohn’s disease is the classic cause of intestinal strictures. Repeated flares of inflammation in the bowel wall lead to scarring that narrows the intestinal passage. Doctors distinguish between two types here: inflammatory strictures, where active swelling is the main problem, and fibrotic strictures, where dense scar tissue has replaced normal tissue. This distinction matters because inflammatory strictures often respond to medications that calm the immune system, while fibrotic strictures are physically fixed and typically require a procedure or surgery to open.
Imaging tools like MRI and contrast-enhanced ultrasound help doctors tell the two apart. On imaging, fibrotic strictures show less blood flow to the intestinal wall and different tissue characteristics compared to actively inflamed segments.
Urethral Strictures
Urethral strictures narrow the tube that carries urine out of the body. The causes break down into four main categories: unknown origin and medical procedures (each accounting for about 33% of cases), trauma (19%), and infection (15%). The balance shifts in different parts of the world. In regions with higher rates of traffic accidents and less developed trauma care, injury-related strictures are more common. In some countries, infection accounts for the majority of cases.
Symptoms include a weak or slow urine stream, straining to urinate, the feeling that your bladder isn’t fully emptying, and frequent urinary tract infections. The initial test is usually a flow rate measurement: a peak flow below 12 mL per second raises suspicion that something is blocking the urethra. In severe cases, you may be unable to urinate at all, which is a medical emergency requiring immediate care.
Biliary Strictures
The bile ducts carry bile from the liver and gallbladder into the small intestine. Strictures here can develop after gallbladder removal surgery, liver transplant, chronic pancreatitis, or autoimmune conditions that inflame the bile ducts. Malignant strictures, caused by pancreatic cancer or bile duct cancer, are also a major concern. Because the distinction between a benign and cancerous stricture changes treatment entirely, doctors investigate biliary strictures carefully using specialized imaging. MRI of the bile ducts (called MRCP) is generally the preferred first step because it’s noninvasive, while more invasive techniques are reserved for obtaining tissue samples when cancer is suspected.
How Strictures Are Treated
Dilation
The most common first-line approach is dilation: physically stretching the narrowed passage open. This can be done with a balloon inflated inside the stricture or with tapered instruments that gradually widen the opening. For urethral strictures shorter than 2 cm, balloon dilation has an overall success rate around 67%, with better results in shorter strictures (about 72%) and in patients between 50 and 60 years old (about 81%). Success drops in patients over 60 and in those who have already had prior procedures, where the success rate falls to roughly 50%.
Dilation works well as a temporary or definitive fix for many patients, but strictures can recur. Newer drug-coated balloons, which release medication to discourage scar tissue from reforming, have shown promising results for recurrent cases, maintaining symptom relief for up to three years in one study.
Stenting
When a stricture keeps returning or is too complex for dilation alone, a stent (a small tube placed inside the passage) can hold it open. Stents come in several materials. Silicone stents are inexpensive, well-established, and available in straight or Y-shaped designs for branching airways. Metallic stents, some partially or fully covered, offer a different profile of flexibility and durability. Biodegradable stents that dissolve over time are also in development. Stents are most commonly used in the airways and bile ducts.
Surgery
For strictures that don’t respond to dilation or keep recurring, surgical reconstruction is often the most durable option. In urethral stricture disease, current guidelines recommend surgery (urethroplasty) as the initial treatment for strictures 2 cm or longer, for strictures in the penile urethra, and for female patients, because endoscopic treatments have high recurrence rates in these situations. Surgical repair often involves removing the scarred segment and reconnecting healthy tissue, or using a graft from the inner lining of the mouth or other donor tissue to widen the passage.
For intestinal strictures in Crohn’s disease, surgery may involve removing the narrowed segment or performing a strictureplasty, where the surgeon widens the narrowed area without removing bowel. The choice depends on the length and location of the stricture and how much healthy intestine the patient has left.
What Symptoms to Watch For
The symptoms of a stricture depend entirely on where it is, but they share a common theme: something that should flow freely is being blocked. In the esophagus, that means trouble swallowing, food getting stuck, or unintentional weight loss. In the urethra, it’s a weak stream, frequent infections, or the inability to fully empty your bladder. In the intestines, it causes cramping, bloating, nausea, and sometimes vomiting after meals if the blockage is severe enough.
Strictures tend to worsen gradually, so symptoms often creep up over weeks or months. The danger point comes when a stricture progresses to complete obstruction: total inability to swallow, urinate, or pass stool. Complete obstruction in any of these systems is an emergency. If you experience sudden, total blockage of something your body normally does without effort, that warrants immediate medical attention.