Eighteen months. Four different foods, two courses of antibiotics, three tubs of something from a pet shop, and a dog who has never once produced a stool you could pick up in one go.
Chronic diarrhoea is one of the most frustrating things to live with, partly because it rarely becomes an emergency, so it drifts. Nobody’s alarmed enough to investigate properly and everybody’s tired enough to keep trying the next food.
It’s worth knowing how a diagnosis is actually reached, because the process is more structured than it looks from the outside, and because most of these dogs can be substantially improved.
What “chronic” means, and what it’s called now
Diarrhoea lasting more than about three weeks, or that keeps returning, counts as chronic. It’s a different problem from a dog who eats something off the beach and is fine by Thursday.
The umbrella term vets increasingly use is chronic enteropathy rather than inflammatory bowel disease. That’s a deliberate change. IBD implies a specific diagnosis, and it was being applied to a mixed group of dogs with quite different underlying problems and quite different treatments.
Chronic enteropathy is honest about that. It says: persistent intestinal disease, cause not yet established, let’s work out which sort.
Which is where daily support has a genuine place rather than a marketing one. Whatever the eventual answer, these dogs have a disrupted gut population, and Probiotics for Dogs fed consistently alongside the diagnostic process is reasonable — not as the treatment, but because a dog going through diet trials, possible antibiotics and possible steroids needs whatever help the population can get. It is not a substitute for finding out what’s wrong.
The three-way split
Chronic enteropathy is classified by what it responds to. That sounds unsatisfying and it’s actually quite practical, because the response is the diagnosis.
Food-responsive enteropathy. Improves on a strict diet trial and stays improved. Comfortably the largest group — most series put it at somewhere around two thirds of cases. Best prognosis by a distance.
Antibiotic-responsive enteropathy, sometimes called dysbiosis. Improves on antibiotics, often relapses when they stop. A smaller group, and one where thinking has shifted considerably.
Immunosuppressant-responsive enteropathy. Doesn’t respond to diet or antibiotics, needs steroids or other immune-modifying drugs. This is what most people mean when they say IBD. Smallest group, most serious, and still very manageable in most cases.
There’s also protein-losing enteropathy, where the gut leaks protein into the intestine. More serious, needs specialist input, and identified by low blood albumin on a routine blood panel.
What gets ruled out first
Before any of that, the obvious things have to be excluded, and this is the step most often skipped.
Parasites. Giardia and whipworm in particular, both of which shed intermittently and are missed constantly on single faecal samples. Ask for pooled samples across three consecutive days. This single request identifies a meaningful proportion of “chronic enteropathy” cases that turn out to be treatable parasites.
Exocrine pancreatic insufficiency. A blood test called TLI. The picture is a ravenous dog losing weight with huge pale greasy stools. Very treatable with enzyme replacement, and missing it wastes months.
Extra-intestinal disease. Kidney, liver, thyroid and adrenal problems all cause digestive signs. A general blood panel covers most of it.
Chronic pancreatitis, via a cPLI test.
Dietary indiscretion, which sounds trivial and accounts for a surprising number of dogs whose owners hadn’t counted the chews.
The bloods worth asking about
Two specific results are unusually informative and don’t always get run.
Vitamin B12, or cobalamin. Absorbed in the last section of the small intestine, so a low level indicates disease there. It’s also worth treating in its own right — B12-deficient dogs respond poorly to everything else until it’s corrected, and supplementation is cheap and effective. This is one of the more commonly missed pieces in chronic cases.
Folate. Often raised where there’s small intestinal bacterial overgrowth.
Together with albumin, they give a useful picture of where in the gut the problem sits and how severe it is.
The food trial, done properly
For most dogs this is where the answer is, and it’s also where most attempts fail.
Two options. A hydrolysed diet, where proteins are broken into fragments too small for the immune system to recognise. Or a novel protein — something the dog has genuinely never eaten. Your vet will pick based on his history.
Six to eight weeks minimum. Digestive signs often improve within two to three weeks; skin signs take longer.
Absolute strictness. This is the whole game. Nothing else at all — no treats, no dental sticks, no chews, no table scraps, no flavoured wormers or joint supplements, no licking plates, no training treats at class.
Most trials fail not because the diet was wrong but because something got in. A single flavoured tablet or one biscuit from a visitor invalidates weeks of work.
Tell every person in the household. Ask your vet whether medications can be supplied unflavoured. And be honest about slips rather than quietly hoping they didn’t count.
Then do the challenge. After a successful trial, reintroduce the old food deliberately. If signs return, you’ve confirmed it. If they don’t, the improvement was something else — time, or a coincidence.
Almost nobody does the challenge, and it’s the step that turns a guess into a diagnosis.
The antibiotic question, which has changed
Metronidazole used to be reached for routinely in chronic diarrhoea. It’s used far more cautiously now, for good reason.
Canine studies have shown it causes substantial and lasting disruption to the gut microbiome, with some bacterial groups not recovering for months. In a dog whose problem may be dysbiosis in the first place, that’s a difficult trade.
Current thinking generally favours diet first, gut support alongside, and antibiotics reserved for cases that genuinely need them rather than as a first move. If your vet is reluctant to prescribe, that’s the evidence rather than obstruction.
Steroids, and what they actually do
For the immunosuppressant-responsive group, prednisolone is usually the starting point.
It works, often dramatically. It also has real side effects at the doses used initially — increased thirst and appetite, panting, muscle loss, and a higher risk of infection. The plan is always to get to the lowest effective dose, and sometimes to add a second drug so the steroid can be reduced.
Two things worth knowing. Steroids disrupt the gut population and increase infection risk, so gut support alongside them is sensible. And don’t stop them abruptly — they need tapering, and stopping suddenly can cause a serious problem in its own right.
Measuring progress properly
Vets use a scoring system for this, and a simplified version at home is genuinely useful.
Score each day out of three or four for stool consistency, appetite, energy, vomiting and weight trend. Write it down. Weigh him weekly on the same scales.
Chronic disease improves slowly and in a wobbly line, and without a record you’ll have no idea whether the last six weeks helped. Owners routinely abandon treatments that were working and persist with ones that weren’t.
Take the record to every appointment. It’s the most useful thing you can hand a vet.
Biopsy: when it’s needed and when it isn’t
The question owners worry about most, and the answer is less dramatic than expected.
Biopsy is what distinguishes the different types of intestinal inflammation microscopically, and it’s the only way to diagnose certain conditions definitively — including lymphoma, which occasionally presents exactly like chronic enteropathy in older dogs.
But most vets won’t start there. The sequence is usually: rule out the obvious, run the bloods, do a properly conducted diet trial. If the dog responds, you have your answer without ever needing a biopsy.
Biopsy moves up the list if there’s weight loss, low albumin, vomiting alongside the diarrhoea, an older dog, or a dog who hasn’t responded to a strict trial.
Two routes. Endoscopic biopsies are taken through a camera passed down the throat and up from the rectum — less invasive, day procedure, but only samples the areas the scope reaches and takes small superficial pieces. Surgical biopsies go through the abdominal wall, sample full thickness and anywhere in the intestine, but it’s abdominal surgery with a longer recovery.
Both need general anaesthesia. Neither is a small undertaking, and both frequently produce an answer that changes the treatment entirely, which is why they’re worth doing when indicated rather than avoided indefinitely.
Diet after diagnosis
If your dog turns out to be food-responsive, the next question is whether he’s on that diet forever.
Often not. A meaningful proportion can be broadened after six to twelve months of stability — introducing one new ingredient at a time, slowly, with a fortnight to assess each. Some end up on an ordinary good-quality food with one or two things avoided.
Others do best staying exactly where they are, and there’s no prize for making it more complicated.
Two practical points. Any hydrolysed or veterinary diet needs to be nutritionally complete for long-term use, which the prescription ones are. And if you’re broadening, change one variable at a time and keep the record going, or you’ll end up back where you started with no idea which addition caused it.
Prognosis, honestly
Food-responsive: good. Many dogs stay well indefinitely on the right diet, and some can eventually broaden it.
Antibiotic-responsive: variable, with relapses common, and increasingly managed with diet and gut support rather than repeated courses.
Immunosuppressant-responsive: usually controllable, often long-term medication, generally a good quality of life.
Protein-losing: more serious and needs specialist involvement, though a proportion do well.
The dogs who do worst are usually the ones who spent two years being managed at home before anyone investigated. Which is the argument for pushing sooner rather than later.
What to actually ask for
Go with a list. It changes the appointment.
Pooled faecal samples across three days, including giardia testing. A full blood panel including TLI, cPLI, B12, folate and albumin. A clear plan for a diet trial, specifying which diet and for how long. A discussion about whether imaging or biopsy is needed, and at what point.
And ask about referral to an internal medicine specialist if you’ve been going round in circles for more than six months. One referral appointment frequently saves a year.
What you can do at the same time
Keep the diet absolutely consistent. Weigh the food. Count everything.
Keep gut support running throughout, particularly around antibiotics and steroids.
Keep worming current, since parasites are the one cause you can remove entirely.
Keep the record. And keep pushing — the single most common feature of chronic cases that eventually get resolved is an owner who stopped accepting that this was just how their dog was.