Lymphangiectasia in dogs means the tiny lymph vessels in the intestine have swollen and started to leak. Protein, fat and white blood cells that should travel into the bloodstream spill into the gut and leave in the stool instead.
Owners usually notice diarrhea, weight loss or a swollen, fluid-filled belly. A vet confirms it with bloodwork, ultrasound and an intestinal biopsy, and the backbone of treatment is a strict low-fat or ultra-low-fat diet chosen by your veterinarian.
The name is literal: lymph (lymph vessels) plus angiectasia (widening of a vessel). It is one of the main causes of a bigger problem vets call protein-losing enteropathy.
What Lymph Vessels in the Gut Normally Do
The small intestine is lined with tiny finger-like projections called villi. Up the middle of each villus runs a thin lymph vessel called a lacteal, and its big job at mealtime is carrying fat. Sugars and protein building blocks go straight into the blood vessels around the villus, but digested fat is packed into tiny droplets called chylomicrons that enter the lacteal instead. From there they travel through larger lymph vessels and the thoracic duct in the chest, which empties into a large vein (Merck Veterinary Manual).
Gut lymph vessels also drain extra tissue fluid, carry fat-soluble vitamins and move immune cells (lymphocytes). The more fat a dog eats, the more fluid has to push through the lacteals.
What Is Intestinal Lymphangiectasia?
In intestinal lymphangiectasia, the lacteals and the lymph vessels deeper in the gut wall become dilated and leaky. When the pressure gets too high, lacteals can rupture and dump protein, fat and lymphocytes into the intestine. Much of it is lost in the stool.
Lymph also irritates tissue. When it leaks into the gut wall and the fat around the intestine, it can set off inflammation and small fat-filled inflammatory lumps called lipogranulomas. Those can block lymph flow even more, so the problem can feed itself.
How it relates to protein-losing enteropathy (PLE)
Protein-losing enteropathy (PLE) is the umbrella name for any gut disease that leaks enough protein to drop blood protein levels. Lymphangiectasia is one of its most common causes in adult dogs, alongside chronic inflammatory gut disease, intestinal lymphoma and some infections. Our guide to protein-losing enteropathy in dogs covers the whole syndrome.
Lymphangiectasia is not the same as gut inflammation (often still called inflammatory bowel disease, or IBD), but the two often travel together. In one study, 76% of dogs with chronic inflammatory gut disease and low albumin also had lymphangiectasia, and a 2019 review of 469 dogs with PLE found lymphangiectasia in 214 of them (46%).
Why the lost protein matters
Albumin acts like a sponge that holds water inside the blood vessels. When it falls, fluid seeps out into the belly, the chest or the skin of the legs and underside. Globulins, which include antibodies and clotting proteins, are often low too, though not always.
Lost fat means lost calories and fat-soluble vitamins, and lost lymphocytes lower the white blood cell count. That combination explains most of what owners see.
Causes and Breeds at Risk
Primary lymphangiectasia happens without another disease driving it. Strong breed patterns suggest a genetic tendency.
Secondary lymphangiectasia develops when something else slows or blocks lymph flow, such as:
- chronic inflammatory enteropathy (IBD)
- intestinal cancers, such as lymphoma or adenocarcinoma
- in theory, conditions that raise pressure in the veins near the heart, such as right-sided heart failure, though this has not been reported in dogs
Breeds reported to be predisposed to intestinal lymphangiectasia include the Yorkshire Terrier, Soft Coated Wheaten Terrier, Maltese, Chinese Shar-Pei, Rottweiler and Norwegian Lundehund. Any breed can be affected, and a predisposed breed is not destined to develop it. French Bulldogs are over-represented in a rare focal form that causes a lump in the intestine (lipogranulomatous lymphangitis).
Basenjis also get a protein-losing gut disease, but theirs is usually a different condition called immunoproliferative enteropathy.
Signs and Symptoms of Lymphangiectasia in Dogs
The most common signs are:
- diarrhea, which may come and go or be constant (our poop color chart helps you describe it to your vet)
- weight loss and muscle wasting
- decreased appetite
- vomiting, less often than diarrhea
- lethargy
- a swollen, fluid-filled belly (ascites)
- swelling of the legs or the underside of the body (edema)
- fast or labored breathing or a cough, when fluid builds up around the lungs
Less common but serious: muscle tremors, face rubbing or seizures from low calcium, and sudden breathing trouble, weakness or lameness, which can mean a blood clot. Dogs with PLE are at higher risk of clots.
In one small study of 17 dogs with lymphangiectasia, every dog had diarrhea, and most also had a poor appetite (82%), lethargy (76%) and vomiting (65%). Even so, some dogs, especially those with primary lymphangiectasia, have little or no diarrhea, so a dog can lose a lot of protein before the stool changes. The signs also overlap with many other diseases, which is why the answer comes from bloodwork and your veterinarian.
When to call your vet
Call now (emergency):
- labored or fast breathing at rest, or a cough with breathing effort
- a belly that is swelling quickly
- collapse or severe weakness
- tremors, twitching or a seizure
- sudden lameness or sudden breathing trouble in a dog already diagnosed with PLE
See your vet soon:
- diarrhea that lasts more than a few days or keeps coming back
- weight loss, even if your dog is still eating
- puffy legs or swelling under the chest or belly
- repeated vomiting or a poor appetite
Mention at your next visit:
- your dog is a predisposed breed and you want to know what to watch for
- your diagnosed dog is stable and you have questions about the diet, treats or rechecks
How Vets Diagnose Lymphangiectasia
There is no single quick test. Vets work through it in steps.
1. Bloodwork. The classic pattern is low albumin, often with low globulin, low calcium, low cholesterol and a low lymphocyte count. In two studies covering 39 dogs with lymphangiectasia, low albumin showed up in 87%, low calcium in 68%, low globulin in 54%, low cholesterol in 51% and low lymphocytes in 46%. Low vitamin B12 and low vitamin D are common too.
2. Ruling out other ways to lose protein. Low albumin can also come from the kidneys or a failing liver, so a urinalysis (often with a urine protein:creatinine ratio) and a bile acids test come next. Specialists also recommend screening for Addison's disease, which can cause a similar drop.
3. Fecal tests look for parasites and infections. A special fecal test (alpha-1 protease inhibitor) can confirm gut protein loss, but it is fiddly and rarely needed.
4. Imaging. Abdominal ultrasound looks for fluid, thickened intestines and bright streaks in the gut lining that can go along with swollen lacteals. Chest X-rays check for fluid around the lungs.
5. Intestinal biopsy. A biopsy read under the microscope is the only way to confirm lymphangiectasia and to see whether inflammation or cancer is also present. Endoscopy is the preferred way to take biopsies in most dogs; some are taken during surgery. The vet may see white spots on the gut lining, which are swollen lacteals. Because the disease can be patchy and is sometimes worse further down in the ileum, specialists recommend sampling the ileum as well as the duodenum.
A very sick dog may not be stable enough for biopsies. Then vets may treat based on the breed, the bloodwork and the response to a low-fat diet.
Treatment: What to Expect
Treatment is tailored to each dog, and your veterinarian chooses every medication and dose. In general terms, it has four parts.
1. Treat the underlying cause. If the lymphangiectasia is secondary to inflammation, cancer or infection, that disease is treated first, and the vet watches whether the protein loss settles.
2. Stabilize the dog if needed. Dogs with very low protein may need hospital care. That can include IV fluids, a feeding tube for dogs that won't eat the new diet, draining fluid from the chest or belly when it makes breathing hard, and in severe cases plasma or albumin transfusions. Transfusions rarely raise albumin for long, because the gut keeps losing the new protein.
3. Diet, the cornerstone. More on this below.
4. Medications and supportive care. Depending on the dog, your vet may prescribe:
- anti-inflammatory steroids, to calm the inflammation that leaking lymph causes in the gut wall. There is no evidence that lymphangiectasia itself is an immune disease, so specialists generally avoid high, immune-suppressing doses
- clot prevention, because dogs with PLE are considered high risk for dangerous blood clots
- vitamin B12 when it is low, and vitamin D support with close calcium monitoring when calcium is low
- anti-nausea and appetite support
Feeding a Dog With Lymphangiectasia
Diet does the heavy lifting. Less fat in the food means less fluid pushing through damaged lacteals, so fewer of them burst and less protein leaks out.
What vets usually aim for:
- A low-fat or ultra-low-fat, highly digestible diet with enough good-quality protein. Your vet picks the level based on how severe the disease is and how much fat your dog was eating before.
- Low fat plus a hydrolyzed or novel protein for some dogs that also have gut inflammation.
- A board-certified veterinary nutritionist for home-cooked diets. Some dogs need a fat level lower than any commercial food, and only a formulated recipe gets that right without leaving gaps in vitamins and minerals.
- Strict trials. No treats, chews, table scraps or food toppers unless your vet approves them. Extra fat makes it hard to tell whether the diet is working. If one diet fails, another might work, so a dog is not written off after one trial.
Please don't build a "low-fat" diet from internet recipes. It is easy to get the fat too high or the nutrients unbalanced, and these dogs have little room for error.
Many dogs do respond. Texas A&M internist Michael Willard notes that albumin often rises markedly within one to two weeks of starting the right diet.
For vet techs and students: Merck no longer recommends medium-chain triglyceride (MCT) oil for lymphangiectasia, because some MCTs still travel through the thoracic duct.
Life Expectancy and Outlook
The picture varies a lot from dog to dog, and the published numbers can sound grim.
- Merck Veterinary Manual reports a median survival of less than 6 months for dogs with PLE in general, with Yorkshire Terriers doing much better (median 44 months).
- A 2019 review of 23 published studies found that 54.2% of dogs with PLE (241 of the 445 with follow-up) died or were euthanized because of the disease.
- Langford Vets (University of Bristol) describes typical survival of months rather than years, while stressing that it varies widely.
Those figures cover PLE from every cause, not lymphangiectasia alone, and the review pools studies from 1977 to 2018, when treatment centered on immune-suppressing drugs. Specialists are more hopeful when lymphangiectasia is caught early: Willard writes that it can be treated successfully in many dogs if diagnosed early. Diet also seems to matter more than once thought. In one study of 43 dogs with PLE (14 with confirmed lymphangiectasia), dogs treated with diet alone had better outcomes than those given immune-suppressing drugs.
What tends to help: an early diagnosis, a strict diet, and every recheck kept so your vet can follow albumin and adjust the plan. Treat the diet as a long-term plan, not a short course. In chronic gut disease, Merck notes that relapses are most often set off by dietary indiscretion. Secondary lymphangiectasia can settle when the underlying disease is brought under control.
Questions to Ask Your Vet
- Is this primary lymphangiectasia, or is something else causing it?
- Which diet should my dog eat, and should we involve a veterinary nutritionist?
- Does my dog need clot prevention or vitamin supplements?
- When should we recheck albumin, and what are we hoping to see?
- Which signs mean I should call you right away?
Originally written by Akosua Kumi Nyarko. Updated by the I Love Veterinary editorial team.
Sources
- Merck Veterinary Manual: Malabsorption Syndromes in Small Animals
- Merck Veterinary Manual: Chronic Enteropathies in Small Animals
- Jablonski SA, Animals (2022): Pathophysiology, Diagnosis, and Management of Canine Intestinal Lymphangiectasia: A Comparative Review
- Craven MD, Washabau RJ, Journal of Veterinary Internal Medicine (2019): Comparative Pathophysiology and Management of Protein-Losing Enteropathy
- Langford Vets, University of Bristol: Lymphangiectasia (owner guide)
- Willard MD, WSAVA 2011 (VIN): Protein-Losing Enteropathies: Diagnosis and Treatment
- Clinician's Brief: Protein-Losing Enteropathy in Dogs (Jablonski SA)
- eClinPath: Globulins
This article is for general information and is not a substitute for advice from your veterinarian.
