Colitis in dogs: What is it and how is it treated?

Colitis is a condition that affects hundreds of dogs each year. But what exactly is colitis? Colitis is a general term for inflammation of the colon, and a variety of factors can cause it.
 
We’re going to explore dog colitis in more detail, answering pet parents' most asked questions on the subject.

What is colitis in dogs?

Colitis is a general term to describe inflammation of the colon. The colon is the lower part of the digestive tract, also known as the large intestine. It connects the small intestine to the rectum, and it is where water, salts, and some nutrients are absorbed. This part of the digestive system turns partially digested food into solid faecal waste. The colon also contains large numbers of microorganisms which help with digestion and immune function.

What are the symptoms of dog colitis?

The most common symptoms of colitis include –

• Loose stools – ranging from soft stools to liquid diarrhoea
• Bloody faeces
• Increased amounts of mucus in the faeces - this may appear as bits of jelly or a pale coating covering the stool
• Passing stools more frequently than normal
• Straining when passing stools
• Reduced appetite
• Abdominal discomfort
  

In more severe cases, dogs can also suffer from –

• Vomiting
• Weight loss
• Dehydration
  

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What causes colitis in dogs?

Many things can irritate your pet’s colon. Some of these are acute, meaning they cause a sudden onset of symptoms which may only last a few days. Other causes may be classed as chronic, with symptoms lasting a few weeks or more. Chronic cases may have symptoms that wax and wane, with flare-ups occurring intermittently.

Common causes include -

Dietary indiscretion

Dietary indiscretion describes dogs that eat things they shouldn’t. These dogs are often scavengers and may eat things like manure, discarded food, and other rubbish. Any of these might cause an episode of colitis. For some dogs, eating things outside of their normal diet, like table scraps, could trigger symptoms, especially if they have a sensitive stomach.

Infections

Bacterial infections like Salmonella and Campylobacter can cause colitis. Dogs that eat raw meat diets being at higher risk of consuming unwanted bacteria. Parasites can also cause mucus or blood in your dog’s stools. The most common ones associated with colitis are microscopic protozoa called Giardia and whipworms (Trichuris vulpis).

Food allergies or intolerances

Some pets may be intolerant to certain things, such as lactose, a sugar found in milk. The gut struggles to process this, resulting in digestive upset. Intolerances are most common to sugars, fats, or additives. In food allergies, the dog has an overactive immune response to a protein within the food, such as chicken or beef. As well as digestive symptoms, this could also result in other signs such as itchy skin, ear issues, or hives. Strict dietary trials are often needed to work out what your pet is reacting to.

Inflammatory bowel disease

Primary inflammatory bowel disease (IBD) can cause colitis and affect dogs to different degrees of severity. Some may have occasional digestive flare-ups, whereas others suffer from constant symptoms, causing secondary issues like severe weight loss.
 
This type of colitis may be identified according to the types of inflammatory cells present in the colon. Lymphocytic-plasmocytic colitis is common, eosinophilic colitis is less frequently diagnosed, and granulomatous colitis (also known as histiocytic ulcerative colitis, or HUC) is rare.  Hypoallergenic diets and supplements like probiotics are the treatment of choice for many dogs with these types of chronic colitis, but some could require medication.

Stress

Stress-induced colitis affects many dogs. In these pets, stress is thought to affect the gut's normal motility, leading to soft poo and mucus. Blood might also be seen. Stress may also weaken immune system function through elevated cortisol levels, which can disrupt the balance of intestinal microbiota. Common stress triggers in dogs include a stay at a boarding kennel, moving house, or the introduction of a new family member to the household (e.g. a new pet or a baby).

Cancer

Tumours could cause colitis, causing symptoms like loose stools, blood, and mucus. Both malignant and benign tumours can develop in the colon or rectum in dogs. A cancer diagnosis will be made with a combination of blood tests, diagnostic imaging, and biopsies.

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How is colitis diagnosed in dogs?

If your dog has a stomach upset, then your vet will begin by examining them. They will also discuss diet and parasite treatment history. During the examination, your vet will check your dog for any abdominal discomfort and assess other parameters, like hydration status, heart rate, temperature, and weight changes.

If acute colitis is suspected and symptoms are mild, then your vet may just suggest symptomatic treatment and monitoring. But if they have any concerns, or if your pet has long-standing problems, they may suggest some further tests. These could include:

• Blood samples are often recommended to screen for underlying health conditions. Your vet may start with routine biochemistry (looking at liver and kidney parameters, blood sugar and protein levels) and haematology (white and red blood cell levels), before ordering more specific tests if needed. This may include folate and cobalamin to screen for absorption issues, or pancreatic lipase to help rule out other concerns like pancreatitis.
• Faecal samples to screen for parasites and bacterial infections.
• Diagnostic imaging like X-rays and ultrasound scans can usefully rule out issues like foreign bodies or tumours.
• A strict dietary food trial may be performed using a food suitable for digestive disorders or a hypoallergenic diet. This can help diagnose food allergies and manage conditions like inflammatory bowel disease.
• Tissue biopsies may be needed for definitive confirmation of some conditions like cancer or inflammatory bowel disease. These can sometimes be collected using an endoscope, or surgery may be required. 
  

The exact plan will depend on your pet's symptoms and your vet's findings. Don't hesitate to ask your vet if you have any questions.

What are the treatment options for colitis in dogs?

The treatment will depend on the underlying cause of your dog’s symptoms.
 
For dogs that have overdone it with treats or eaten something they shouldn’t have done, then a few days of bland food and some probiotic supplements to support their gut usually does the trick. Dogs with stress-induced colitis usually respond well to this too, but you may need to take steps to manage their anxiety too. Anti-anxiety medications, synthetic calming pheromones, or a change in their environment may help to support them.
 
For others, anti-parasite products will be recommended if they have an underlying worm or Giardia infection; antibiotics may be required for animals with bacterial infections, and a change in diet may be advised for animals with suspected food allergies or inflammatory bowel disease. Ongoing probiotic support can be helpful in many cases, to ensure your dog has a healthy microbiome and immune function.
 
Severely affected cases may need to be admitted for intravenous fluids and supportive treatment. This may be required if your pet has vomiting, abdominal pain, or profuse diarrhoea. They may need anti-nausea medications and pain relief, with some needing to remain hospitalised until their symptoms improve.
 
However, the good news is that many cases of colitis can be successfully managed with home care following your trip to the vet. Your vet will be able to advise you, depending on your pet’s needs.

Summary

If your pet often suffers from loose stools, or they have blood and mucus in their faeces, then they could be suffering from colitis. It's always best to get your dog checked out, as there could be an underlying reason for these symptoms, such as an infection or inflammatory bowel disease. Your vet will work things out with you and suggest a course of action to help your dog feel more comfortable again.