Mucosal healing occurs when there are no signs of inflammation or lesions in the mucosa, the inner lining of the bowel wall.

Crohn’s disease is a type of inflammatory bowel disease that can cause inflammation anywhere in the digestive tract, most commonly the small intestine and the beginning of the large intestine (colon). It’s typically treated with medication, bowel rest, and potentially surgery.

One goal of treatment is to reduce lesions in the lining of the colon. Mucosal healing is when a doctor finds no signs of inflammation or lesions when using an endoscope to look at the colon, such as during a colonoscopy. This is associated with better clinical outcomes and improved quality of life.

Mucosal healing can take weeks or months. Some people might experience partial healing or none at all. Endoscopic assessment is the only way to know whether this healing is taking place.

Even if you experience mucosal healing, Crohn’s disease might still be active. A doctor can use additional assessments to monitor the condition.

Crohn’s disease causes inflammation and irritation in your digestive tract. The condition is chronic, which means it persists for a long time.

The inflammation in Crohn’s disease extends through several layers of the bowel wall, from the mucosa to the serosa. The mucosa is the inner layer of the bowel wall, just under the interior surface of the colon. It absorbs water and some nutrients from the food you eat. It also produces mucus that helps stool move easily through your colon and rectum.

Complications of Crohn’s disease can arise from this inflammation through all layers of the bowel wall, called transmural inflammation. Those complications include the thickening of the gastrointestinal walls and narrowing of the digestive tract.

Narrowing of the digestive tract can cause damage to the lining of the intestines as well as fistulas and abscesses. Using endoscopy, doctors can usually see ulcers on the bowel wall.

Mucosal inflammation refers to the inflammation of the mucosa, the inner lining of the bowel wall.

Mucosal healing is when the mucosal layer of the bowel wall has begun to improve. Typically, this is defined as having no ulcers on the bowel wall, but doctors and researchers have varying definitions of mucosal healing.

Healing might be complete or partial. Partial mucosal healing is when there’s improvement only in large or deep ulcers.

Mucosal healing is often a treatment goal for Crohn’s disease. In the past, doctors aimed to control symptoms, but a lack of symptoms didn’t mean that there was no disease activity. As knowledge about the condition increased, mucosal healing became more important.

Mucosal healing, based on older research, is associated with better long-term outcomes, such as lower rates of abdominal surgery.

Doctors typically evaluate the mucosa using an endoscope, a long flexible tube with a light and camera attached to it. Endoscopic techniques, such as colonoscopy, are essential to diagnose Crohn’s disease and to assess response to treatment.

If a doctor doesn’t find any evidence of inflammation using an endoscope, it’s known as mucosal healing.

According to a 2020 article in the journal Gastroenterology and Hepatology, in the past, the terms mucosal healing and endoscopic healing meant the same thing. The term mucosal healing now includes both endoscopic healing and histological healing. Histological healing is when no evidence of inflammation is found when tissue is observed under a microscope.

Some researchers have noted that endoscopy does not assess healing, or lack of healing, in all layers of the bowel wall. Since Crohn’s disease is transmural (affecting all layers), some have said that another imaging technique that can assess healing in all layers is necessary.

While cross-sectional imaging might be the ideal way to assess transmural healing, it’s not currently in widespread clinical use.

Treatment guidelines recommend assessing the bowel 6 to 9 months after starting a new Crohn’s disease therapy. The mucosa can begin to heal sooner or later than this timeline.

In one paper that reviewed past clinical studies on various treatment options to achieve mucosal healing, treatments worked in as short as 10 weeks and as long as 12 months.

A doctor can assess whether the lesions inside the colon are healing by using endoscopy. They’ll use standard scales such as the Crohn’s Disease Endoscopic Index of Severity (CDEIS) or the Simple Endoscopic Score for Crohn’s Disease (SES-CD).

Mucosal healing does not always mean Crohn’s disease is in remission. It doesn’t take into account all layers of the bowel wall. A doctor can also use other methods to monitor Crohn’s disease activity, such as biomarkers like C-reactive protein and direct bowel tissue examination (histopathology).

Complete mucosal healing can take time and is not possible for everyone. If it can be achieved, however, it’s associated with better quality of life. People may experience fewer relapses, reduced use of steroids, fewer hospitalizations and colon surgeries, and better ability to work.

Crohn’s disease is the result of intestinal inflammation that impacts all layers of the bowel wall. One treatment goal is to heal the mucosal layer. Mucosal healing is associated with better quality of life.

It can take a few weeks to several months for the mucosa to heal. Other indicators of disease activity, such as biomarkers and histopathology, are also important to monitor the condition.