Diabetes in Dogs: Symptoms, Causes, Treatment and Care

Diabetes in dogs is one of the most common long-term health conditions seen by vets across the country. Research from the Royal Veterinary College shows that around 1 in 300 dogs in the UK develop diabetes mellitus - the most common form of canine diabetes. Recent data also revealed that the number of dogs receiving insulin for diabetes at PDSA hospitals has risen by almost 10% in just five years, showing that more dogs are getting access to the treatment they need. 

While dog diabetes can’t be cured or reversed, it can be successfully controlled with insulin therapy, a balanced diet, consistent exercise and routine monitoring, allowing most dogs to live long, active, and happy lives. 

This guide explores everything you need to know about diabetes in dogs, including what causes it, how to spot the symptoms, which breeds are most at risk, and how treatment and daily care can help your dog continue to thrive.

In this article: 

1. What is diabetes in dogs?
2. Symptoms of diabetes in dogs
3. What are the causes and risk factors of diabetes in dogs?
4. Complications of canine diabetes
5. Diagnosing diabetes
6. How to treat diabetes in dogs
7. Can diabetes in dogs be prevented?
8. Conclusion

What is diabetes in dogs?

Just like in humans, diabetes in dogs is a condition that affects how the body controls blood sugar. Most mammals produce the hormone insulin, which helps to stabilise blood sugar levels after eating. With diabetes, this normal process is impacted - either the pancreas doesn’t produce enough insulin, or the body stops responding to it as it should.

Diabetes mellitus is the most common type of diabetes in dogs, and while there are technically two forms - one caused by a lack of insulin (similar to Type I diabetes in humans) and one caused by insulin resistance (similar to Type II diabetes) - most dogs are affected by the insulin-deficiency type.

A less common type, diabetes dioestrus, can occur in unspayed female dogs during their heat cycle. Hormonal changes at this stage can interfere with insulin’s normal action, leading to temporary diabetes. 

While rare, dogs can also develop diabetes insipidus, a completely different condition that affects water balance rather than blood sugar. It’s caused by a problem with the hormone vasopressin, which regulates water retention.

Symptoms of diabetes in dogs

Because diabetes develops gradually, it’s easy to mistake the first signs for normal ageing or mild illness in your dog. That’s why it’s important to be aware of the different symptoms so you can get an early diagnosis and prevent any serious complications.

Early symptoms of diabetes

In the early stages, you may notice subtle but persistent changes in your dog’s habits or appearance, such as:

• Drinking more than usual (increased thirst)
• Urinating more frequently
• Increased appetite or, alternatively, a loss of appetite
• Weight loss despite eating normally
• Tiredness, weakness or lethargy
• Dull or thinning coat

Advanced or serious signs

As diabetes progresses, more noticeable or severe symptoms can appear, including:

• Sweet or fruity-smelling breath
• Cloudy eyes (often due to cataracts)
• Vomiting or signs of dehydration
• Recurring urinary tract or skin infections
• Collapse or coma (signs of diabetic ketoacidosis, a medical emergency)

If you notice these symptoms of diabetes in your dog, contact your vet immediately. 

What are the causes and risk factors of diabetes in dogs?

Diabetes rarely has a single cause: it can develop through a mix of genetic, hormonal, immune and environmental influences. Being aware of these risk factors can help you reduce the chances of your dog getting diabetes, or help to manage their condition better. 

Age and genetics

As with many health conditions in pets, some dog breeds are more prone to diabetes than others, and age increases their risk. The latest large-scale UK study analysing over 1,000 dogs from the UK Canine Diabetes Register and VetCompass found that:

• The highest-risk breeds were the Samoyed, Tibetan Terrier, Dachshund, Cairn Terrier, and Miniature Schnauzer.
• Lower-risk breeds included the Boxer, German Shepherd, Golden Retriever, and Pug.

Older dogs are more likely to develop diabetes because over time, their pancreas becomes less efficient and their tissues less sensitive to insulin. In the same UK study, most cases of diabetes were diagnosed in middle-aged and senior dogs aged 7-11 years old (with a median age of around 9). This again varies by breed, with some breeds including Dobermans, Rottweilers and Cavalier King Charles Spaniels more likely to develop diabetes at a younger age.

It’s unclear why certain breeds are more likely to get diabetes than others, or get it earlier in their lives. However, just because your dog may be at risk, doesn’t mean they’ll definitely develop the condition. Other factors also play a role, as we’ll explore below.

Health conditions and medications

Certain health problems and prescription medications can raise the risk of diabetes by affecting insulin production or response. Common examples include:

• Pancreatitis: Chronic inflammation of the pancreas can damage your dog’s insulin-producing cells.
• Obesity: If your dog is obese or over their ideal body weight, the ability of their cells to take up insulin from the blood may be reduced. We call this insulin resistance, and it leads to increased glucose levels in the blood that drive the symptoms seen in diabetic animals.
• Corticosteroid use: Nine percent of dogs with diabetes were diagnosed within 6 weeks of receiving a course of steroids, according to a 2023 VetCompass study. In contrast, the use of antibiotics in dogs did not appear to increase the risk of diabetes mellitus diagnosis.

Immune and inflammatory causes

In many dogs, diabetes mellitus is associated with chronic inflammation, with the immune system potentially contributing to the loss of insulin-producing beta cells in the pancreas. This process is similar to autoimmune mechanisms seen in Type 1 diabetes in humans, with recent research suggesting that inflammation plays a significant role in triggering this destructive process. High numbers of an inflammatory white blood cell called Th40, are found in blood samples from dogs with confirmed diabetes mellitus, compared to non-diabetic dogs. This finding supports the medical view that diabetes in dogs is caused by autoimmune processes, like the same condition in humans.

Hormonal and reproductive factors

Hormones play a big role in your dog’s overall health. Sometimes, changes in hormone levels can affect how their body controls blood sugar.

Cushing’s disease (hyperadrenocorticism) is a condition that causes the body to produce too much of the stress hormone cortisol, which can make it harder for insulin to do its job, leading to high blood sugar.

Female dogs are also at risk of developing dioestrus diabetes during their heat cycle. When the hormone progesterone rises, it can interfere with insulin’s normal action. In many cases, spaying helps resolve or prevent this type of diabetes in dogs. 

Complications of canine diabetes

Even with careful management, diabetes can affect other parts of your dog’s body over time. Regular check-ups are vital, as many complications can be detected and treated before they cause lasting harm.

Complications can include:

• Cataracts: This is the most common long-term complication. Cataracts are cloudy or opaque lenses that can develop rapidly due to high blood sugar levels. One study has found that 12% of diabetic dogs had cataracts by the time of diabetes diagnosis, and within 1 year, 75% of cases had developed cataracts, despite starting insulin therapy (Beam et al 1999). Many diabetic dogs lose vision, but cataract surgery is often successful in restoring sight.
• Pancreatitis: As well as being a key risk factor in your dog developing diabetes, inflammation of the pancreas that can worsen diabetes control and cause abdominal pain or vomiting.
• Urinary tract infections: Excess sugar in your dog’s urine provides a perfect environment for bacteria to grow.
• Diabetic ketoacidosis (DKA): A serious, life-threatening emergency caused by dangerously high blood sugar and ketone buildup. Dogs may vomit, appear weak, or collapse.

Diagnosing diabetes

Because many early signs of diabetes in dogs can mimic other illnesses, lab testing is essential for an accurate diagnosis. Your vet will be able to confirm diabetes using a combination of tests, often repeated over time to ensure consistent results. These can include: 

• Blood glucose measurement: Tests for persistently high sugar levels (over 11.1 mmol/L / 200 mg/dl), which is a key indicator of diabetes.
• Urine analysis: Your vet will check your dog’s urine for the presence of glucose or ketones, which signal poor insulin control.
• Fructosamine test: A blood test to measure the average blood glucose levels over the last 1-3 weeks, commonly performed in vet practice.
• HbA1c tests: Although a relatively new test in dogs, HbA1c has been used to monitor human diabetics for decades. This test assesses blood glucose control over the last 2-3 months, offering a useful monitoring tool to diabetes cases seen in practice.
• Blood glucose curves: Your vet may suggest tracking blood sugar at intervals throughout the day to see how well insulin and feeding routines are working.
  As we’ve explored, early and accurate diagnosis offers the best chance of achieving stable blood sugar control and avoiding any long-term complications.

How to treat diabetes in dogs

For most diabetic dogs, once or twice daily insulin injections are recommended to keep blood glucose levels under control.

In the UK, the most common insulin products are:

• Caninsulin® (porcine lente insulin): Currently the most popular product for managing dog diabetes.
• ProZinc® (protamine zinc insulin): A longer-acting option that’s been growing in popularity since 2019.

Your vet will determine the correct insulin type, dose, and timing based on your dog’s weight, diet, and response to treatment. Ongoing monitoring using fructosamine tests or blood glucose curves helps ensure the dose remains safe and effective. 

Researchers stress that success largely depends on owner confidence and consistency. Giving injections at the same times each day, storing insulin correctly, and following your vet’s guidance are all key in managing your dog’s diabetes.

Diet and feeding

A controlled, balanced diet plays a vital role in regulating your dog’s blood sugar. Veterinary nutritionists recommend:

• High-protein, moderate-fibre, and low-fat meals to slow glucose release.
• Avoiding sugary treats and table scraps, which can trigger spikes in blood sugar.
• Feeding at consistent times each day, ideally just before or at the time of insulin injections.

Some dogs may also benefit from prescription diabetic diets, designed to promote steady energy levels and support weight management.

Exercise and routine

Regular, moderate exercise helps regulate insulin requirements, improve circulation, and prevent obesity. 

To keep blood sugar stable, try to stick to a consistent routine and avoid sudden increases or decreases in activity. Always monitor your dog for signs of fatigue or unsteadiness after vigorous play as this may signal a drop in blood sugar.

Monitoring at home

As well as the steps above, it’s often a good idea to keep a daily log of:

• Appetite and thirst
• Urination frequency
• Body weight
• Energy levels

If your dog shows signs such as trembling, weakness, or disorientation, they may be suffering from low blood sugar (hypoglycaemia). In case of an emergency, rub honey or corn syrup on their gums, and contact your vet immediately.

Can diabetes in dogs be prevented?

Not every case of diabetes in dogs can be prevented - especially those with strong genetic or autoimmune risks. While you can’t control genetics, you can manage the modifiable risk factors, giving your dog the best chance at avoiding this long-term condition altogether:

• Keep them at a healthy weight: Obesity is linked to insulin resistance and can make diabetes harder to control.
• Feed them a high-quality, balanced diet: Choose complete, vet-approved dog food rather than calorie-dense or fatty treats.
• Avoid unnecessary corticosteroid use: These medications can increase diabetes risk, particularly in genetically predisposed breeds.
• Schedule regular vet check-ups: Routine blood and urine tests can detect early changes before diabetes develops.
• Discussing spaying with your vet: Unspayed females are at higher risk of hormone-related (dioestrus) diabetes, and spaying at the right time can prevent it.

Conclusion

A diabetes diagnosis can be daunting, but with the right care and consistency, it’s a condition that can be successfully managed. From recognising the early warning signs of diabetes in dogs to understanding the importance of insulin, diet, and routine, you now have the tools to help keep your pooch healthy and happy.

By working closely with your vet, sticking to regular check-ups, and maintaining a balanced lifestyle, your dog can continue to enjoy the things they love most, from long walks to cosy nights in. With knowledge, patience, and support, diabetes doesn’t have to change your dog’s life - it just becomes part of their routine.

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• Dog health problems advice