Hospital-coded inflammatory bowel disease is rising sharply. Irritable bowel syndrome is not. That gap may be one of the most important post-pandemic signals we are missing — or it may be a trap if we interpret it too quickly.
Between 2016 and 2025, Crohn’s disease and ulcerative colitis rose markedly in NHS Hospital Episode Statistics. In my current analysis, Crohn’s disease is up around 48% above the pre-pandemic baseline, ulcerative colitis is up around 73%, and combined inflammatory bowel disease activity is up about 60%. Yet several functional or non-inflammatory gut codes did not rise in the same way. Irritable bowel syndrome went slightly down. Functional intestinal disorders fell. Malabsorption did not show the same rise.
That asymmetry is why I keep coming back to the gut. Not because the gut is fashionable. Not because every problem reduces to diet. And not because I think inflammatory bowel disease is being created from nothing. I keep coming back because if the intestine were simply seeing “more of everything,” the low-acuity functional codes should have risen too. They did not.
Still, the objection matters. Other gastrointestinal activity also rose. Gallstones rose. Pancreatitis rose. Appendicitis rose. Some hernia codes rose. Several of these are not immune-mediated inflammatory bowel diseases, so their rise forces me to take the broader post-pandemic gastrointestinal activity tide seriously. I cannot lazily say, “IBD rose, therefore COVID caused IBD.” The better question is narrower and more interesting: why are inflammatory bowel codes rising strongly while functional bowel codes are not?
The disciplined interpretation
The strongest interpretation is not that all gut disease is rising. It is more specific than that. The inflammatory bowel disease signal appears selective against functional bowel disease. It is not fully selective against the wider gastrointestinal tide. That distinction matters.
If everything had moved in the same direction — IBS, functional bowel disorders, malabsorption, Crohn’s, ulcerative colitis, gallstones, hernias, appendicitis, pancreatitis — I would be much more cautious. That would look like general healthcare activity, service recovery, coding changes, or delayed access. But that is not the pattern. The inflammatory codes are moving strongly. The functional codes are not.
So the question becomes whether the gut is showing us a shift toward inflammatory disease being unmasked, amplified, or made more complex after the pandemic. This is where I use the word unmasking. I do not think repeated exposure creates inflammatory bowel disease from nothing. That is too simplistic. The data do not prove that, and the biology does not require it. The more plausible model is that people with subclinical gut inflammation, genetic susceptibility, autoimmune tendency, prior gut symptoms, impaired barrier function, or microbiome disruption are being pushed over a threshold they were already close to.
There were already embers. Repeated inflammatory exposure may be petrol on those embers.
Crohn’s and ulcerative colitis are not the same disease
Crohn’s disease and ulcerative colitis are often grouped together as inflammatory bowel disease, but they are not the same condition. Crohn’s is often patchy, can affect different parts of the gut, and can involve deeper layers of the bowel wall. Ulcerative colitis usually affects the colon and rectum, and tends to involve the inner lining in a more continuous pattern.
Different diseases. Different anatomy. Different behaviour. Yet both are rising. That raises the possibility that the common denominator is not one specific diagnosis. It may be a broader inflammatory pressure being applied to vulnerable intestinal tissue — and that tissue then fails in whichever pattern that individual was already predisposed to.
That is the idea I am testing. A framework for broad increased intestinal inflammation.
Why the intestine matters beyond digestion
Most people still picture the gut as plumbing. Food goes in, nutrients are absorbed, waste comes out. That is true, but it is not the important part of this story.
The intestine is one of the body’s largest immune surveillance systems. Every day it has to decide what to tolerate and what to attack. It is exposed to food antigens, bacteria, fungi, toxins, viral particles, immune cells, inflammatory mediators, and the metabolic products of the microbiome. It has to get that judgement right constantly.
If that system becomes destabilised, there is no reason to assume the consequences will remain confined to the bowel. The intestine is a living border between the outside world and the immune system. If that border becomes inflamed, leaky, or immunologically unstable, the effect may extend beyond gut symptoms. It may influence fatigue, joint pain, skin disease, eye inflammation, neurological symptoms, immune flares, and broader inflammatory patterns.
That is why I do not see this as simply a gastroenterology issue. I see the gut as a possible amplifier — not just another organ affected by the pandemic, but one of the places where post-pandemic inflammation may be sustained, multiplied, and exported to the rest of the body.
