Diarrhoea in dogs and puppies: causes, diagnosis and treatment

Diarrhoea is a common ailment affecting both dogs and puppies, but in very young puppies it can be particularly serious and may require urgent veterinary attention. Persistent diarrhoea can lead to dehydration and even hospitalisation, so it is essential to understand its causes and how it can be managed responsibly.

When a vet assesses a dog with diarrhoea, they seek to determine the underlying reason, which can greatly influence treatment. Diarrhoea is broadly classified as either primary intestinal or secondary, indicating whether it originates from the digestive tract itself or is a symptom of another disease. A thorough history-taking from the owner greatly assists diagnosis.

Primary Intestinal Diarrhoea: Diagnosis and Signs

Primary intestinal diarrhoea arises directly from problems within the intestines. Crucially, vets differentiate whether the small or large bowel is affected, as this influences symptoms and treatment:

• Weight loss: Often present with small bowel disease but rare with large bowel problems.
• Faecal volume: Increased volume suggests small bowel involvement; reduced volume points to large bowel disease.
• Faecal blood: Fresh blood in stools usually indicates large bowel disease, whereas dark, tarry stools point to small bowel bleeding.

Common Causes of Primary Intestinal Diarrhoea

There are multiple causes, some mild and transient, others requiring detailed treatment:

• Infectious agents: Viral infections such as canine parvovirus, distemper virus, coronavirus, and bacterial infections including salmonella and campylobacter.
• Parasitic infections: Including hookworms, whipworms, giardiasis, and roundworms, which commonly affect puppies.
• Inflammatory conditions: Colitis, an inflammation of the colon, can be serious and often requires veterinary intervention.
• Tumours and neoplasia: Less common but important to consider in persistent cases.

Colitis can arise due to infections, hypersensitivity to food, parasites, or even cancer of the colon. Inflammatory bowel disease (IBD) is another cause, where chronic inflammation leads to malabsorption and persistent diarrhoea.

Secondary Causes of Diarrhoea

Secondary diarrhoea occurs when the stool abnormality results from a non-intestinal disease. Some important conditions include:

• Addison's disease: A hormonal disorder affecting electrolyte balance.
• Kidney failure: Toxin buildup may cause gastrointestinal upset.
• Liver disease: Can cause a range of systemic effects, including diarrhoea.
• Hyperthyroidism: Increasing metabolic rate and leading to digestive disturbances.
• Exocrine pancreatic insufficiency (EPI): This is a condition causing a lack of digestive enzymes, leading to maldigestion and diarrhoea.

How Diarrhoea is Diagnosed

Diagnosis typically involves a combination of clinical examination and specialist lab testing. Vets may ask you to collect a faecal sample to check for parasites, undigested food, and bacterial infections such as salmonella or campylobacter. In some cases, advanced diagnostics like endoscopy and intestinal biopsies are used to assess inflammation or tumours.

Treatment Options for Primary Intestinal Diarrhoea

Caring for a dog with diarrhoea depends on severity. Mild cases may be managed at home, but puppies or dogs with severe symptoms often need hospitalisation for fluid therapy and supportive care:

• Withholding food for 24-48 hours: This rest period helps the digestive system recover.
• Hydration support: Ensuring adequate fluids at home with electrolytes or by intravenous drip if hospitalised.
• Antibiotics: Used only when a bacterial infection is confirmed to prevent unnecessary resistance and side effects.
• Diet: After the fasting period, small amounts of a low-fat, vet-recommended diet are introduced gradually. For chronic cases, lifelong specialised diets may be needed.

Treatment for inflammatory bowel disease and colitis includes feeding hypoallergenic, gluten-free diets and administering anti-inflammatory medications to calm the gut. Antibiotics may also be used sporadically to manage bacterial overgrowth.

When to Contact Your Vet

If your dog or puppy has diarrhoea coupled with signs of lethargy, weakness, vomiting, or dehydration, seek veterinary advice promptly. Early care can prevent severe complications and promote a quicker recovery.

How long should I wait to feed my dog after diarrhoea?

Quick Answer: Typically, dogs are fasted for 24 to 48 hours after diarrhoea onset to rest their digestive tract, after which a bland, low-fat diet is gradually reintroduced.

After diarrhoea starts, withholding food for one to two days can help the intestines heal and reduce irritation. Water must be freely available during this time to prevent dehydration. Following fasting, feeding small amounts of easily digestible, low-fat food recommended by your vet helps restore gut health without causing further upset. Reintroduction to regular food should be gradual to prevent recurrence.

Can diarrhoea in dogs be contagious to humans?

Quick Answer: Some causes of dog diarrhoea, such as bacterial infections with salmonella and campylobacter, can be zoonotic, meaning they may be transmitted to humans, so good hygiene is essential.

Campylobacter and salmonella are among the bacterial infections that cause diarrhoea in dogs and can be passed to people, especially if hygiene measures are inadequate. Handling dog faeces, contaminated food, or water requires careful hand washing. Vulnerable people such as young children, elderly, and immunocompromised individuals should take extra precautions to avoid infection. Always follow your vet's advice to reduce zoonotic risks.

Responsible Dog Ownership and Prevention Tips

Preventing diarrhoea involves responsible care including keeping vaccinations up to date to protect against viral diseases, routine parasite control through worming, feeding high-quality diets, and avoiding letting dogs eat garbage or unknown substances. Early vet intervention at any sign of illness can reduce severity and duration of diarrhoea. Regular health checks and hygiene habits are key to keeping your dog healthy and happy.

When acquiring a new puppy, it is essential to buy from reputable breeders or adoption centres to ensure good health and reduce risk of infections. Proper vaccination and parasite treatments are fundamental early in a puppy's life.

By understanding diarrhoea in dogs and puppies, recognising signs early, and acting with prompt veterinary care, you can help your beloved pet stay well and recover swiftly.