7 Signs of Illness to Look Out for in Dogs

Understand the signs of illnesses in dogs and how you can keep them healthy.

Mar 19, 2025byDonna Hobson

signs of illness to look out for in dogs

 

Dogs communicate with us in their own way; we can often tell if they’re happy, hungry, or angry. Still, when they’re sick, it’s hard for them to let us know something’s wrong and even more challenging for them to tell us what that something is.

 

That’s why it’s important to know what the signs of illness are in your dog and what they mean for their overall health. If you notice any of the following symptoms in your dog, schedule an appointment with their veterinarian.

 

1. Behavioral Changes Could Indicate Pain or Discomfort

tired dog by shoe
A Boxer next to a shoe. Credit: Image by Engin Akyurt on Pixabay

 

We spend considerable time alongside our canine friends, so we get to know their personalities and general behaviors. This makes it easier for us to spot when something might be wrong.

 

If your dog has less energy than usual, it could be a sign that something is wrong. Pay attention to them if they start to run around less, play less, or seem a little run down.

 

Many dogs love a good mix of attention and affection. If you notice that stroking or cuddling your dog is beginning to be met with resistance, it could signify that they are struggling with an internal injury or broken bone.

 

If they seem sensitive when touched, take them to a vet who can assess their body for injury.

 

2. Changes in Eating or Drinking Habits

dog drinking water
A dog drinking water from its owner’s hand. Credit: Image by Matan Ray Vizel on Pixabay

 

Our digestive system and processes can say a lot about our general health; the same is true for your canine. Keeping an eye on their eating patterns, toileting, and waste can quickly show if something is wrong.

 

It’s vital for your dog to drink plenty of water during the day; still, excessive thirst could indicate that something is wrong with your canine. If you notice that your dog’s urine is darker than usual, it could signify that they’re dehydrated.

 

Changes in appetite also indicate that something untoward could be going on. If their eating or drinking habits change noticeably, don’t wait; refusing to eat or drink could signify a veterinary emergency.

 

3. Vomiting or Diarrhea: A Possible Gastric Problem

day laying down
A dog lying on its side. Credit: Image by Diana on Pixabay

 

Vomiting can occur for several reasons, including your dog getting into the trash or ingesting a foreign object. But, vomiting can also be a sign of a bacterial or viral infection that requires treatment, such as parvovirus, which is especially common in puppies.

 

Keeping an eye on your dog’s poop is also an excellent way to monitor their general health. Check the texture and composition regularly; runny or bloody waste could be a sign of ill health. This is also a good time to check their poop for anything that shouldn’t be there, such as shredded tissues or stuffing from toys.

 

Vomiting and diarrhea are among your dog’s most common symptoms of ill health. If these symptoms occur frequently, book an appointment with your vet as soon as possible.

 

4. Changes in Urination Could Mean Kidney Problems

dog urinating against tree
A dog peeing on a tree. Credit: Image by Gianni Crestani on Pixabay

 

An increase or decrease in your dog’s urination frequency can signal a health issue. It’s very unusual for a once-trained house-trained dog to start urinating in random places.

 

Keep an eye out for changes in urination frequency, straining to go to the toilet, or having blood in their urine. These are all indicators – particularly in older dogs – that your canine could have a urinary tract infection, kidney issues, or diabetes.

 

If you spot any of these symptoms, book an appointment with your vet as soon as possible and bring a sample of your dog’s urine for testing.

 

5. Physical Symptoms, Like Sudden Weight Loss

cocker spaniel dog
A dog looking upward. Credit: Image by Fran @thisisfranpatel on Pixabay

 

Physical symptoms are often the easiest to spot, and checking your dog’s fur, skin, and bones can be an excellent way to monitor their health.

 

Once your dog reaches adulthood, its weight should remain consistent. If your dog suddenly drops a lot of weight, it could mean that something is wrong. In contrast, being overweight is not good for your dog’s health either, so you’ll want to supply them with a consistent and nourishing diet to meet their needs adequately.

 

Regularly check the fur and skin of your canine, particularly when they come up for a cuddle, and you can get close to them. Examine the fur for changes in color or texture, and check the skin for cuts, lesions, or anything else unusual.

 

The eyes should be white, and the outer layer (called the cornea) should be transparent. If you notice any discoloration or cloudiness in your dog’s eyes, speak to your vet for the best advice. In addition, your dog has a third eyelid called a nictitating membrane. This should not be visible unless your dog has just woken from a long sleep.

 

6. Problems Walking or Running

puppy running through water
A dog running through a puddle. Image by Rudy and Peter Skitterians on Pixabay

 

Finally, keep an eye on your dog’s movements; if they walk with a limp or in a different way than usual, it could be a sign that they have an internal problem with their bones or muscles. Difficulty walking can be caused by arthritis, joint problems, hip dysplasia, infection, or a broken bone.

 

A funny walk could indicate something stuck in their paw, causing them pain. If you notice that your dog is walking differently than usual, examine their feet for any foreign bodies, then gently touch the surrounding areas to see if they experience any sense of pain.

 

7. Persistent Coughing and Sneezing Indicate Respiratory Issues

cute puppy lay down
A small dog on a white surface. Credit: Image by roseannc on Pixabay

 

Coughing, sneezing, nasal discharge, or difficulty breathing indicate a potential respiratory infection. These could be several common cold infections, kennel cough, or canine flu.

 

A moderate amount of coughing or sneezing should be closely monitored; if your dog’s condition doesn’t improve or their symptoms worsen, seek help from your vet. Respiratory symptoms become a medical emergency if your dog struggles to breathe or has blue gums. In this case, talk to your emergency vet immediately for the best advice.

 

 

 

Donna Hobson
byDonna Hobson

Donna believes that keeping a pet is the key to a happy life. Over the years, many creatures have passed through her home - Sooty the cat, Millie the rabbit, Stuart (Little) the guinea pig, and Trixie the tortoise, alongside her pet goldfish, Zippy, who lived to the grand old age of 24 years! She currently resides with her black kitten Jinx and an aquarium full of fish and snails to entrance them both. When she is not looking after her pets, Donna enjoys researching and writing the answers to all your pet-related wonders.