As a dog mom, you know your dog better than anyone else in the world. You’re the one who notices when they are extra bouncy, begging for scraps from the table (always!) and when something is just not right about your pup. Yet, there are some early signs of illness in dogs that are quite subtle.
Due to the instinctive urge of dogs to hide from weakness (another survival instinct from their wild ancestors), it is possible that by the time your dog is displaying signs of illness, it may be more serious than it first appears.
Keep reading to find out five signs of illness in dogs that are worth noting – even if your dog seems fine the majority of the time.
Sign 1: Drinking More Water Than Usual
A dog who suddenly can’t get enough water is not a quirk that every dog owner wants to have in their pets. Increased thirst (polydipsia) is a common symptom of several illnesses – such as diabetes, kidney disease, Cushing’s disease, and pyometra.
If your dog is drinking a lot more than normal or going outside to urinate more than before, note the amount of water your dog is drinking and mention this to your veterinarian at your next visit – or sooner if you notice this behavior emerging suddenly.
Watch out for pyometra
Excessive thirst combined with lethargy, loss of appetite, or unusual discharge can be a sign of pyometra — a life-threatening uterine infection in unspayed female dogs. Learn more about pyometra here.
Sign 2: A Subtle Change in Energy or Enthusiasm
This one is hard to pin down, which is exactly why it gets missed. Your dog isn’t collapsing or refusing to move — they just seem a little less interested in their walk, a little slower to get up, or slightly less excited about their favourite toy. You might tell yourself they’re just having an off day.
But you know your dog’s normal. A persistent dip in energy — lasting more than a day or two — is worth noting. Low-grade lethargy can be an early sign of pain, infection, anaemia, or hormonal issues. It’s the kind of thing that feels minor until it isn’t.
Tip: Trust your gut. If something feels different about your dog’s energy and you can’t explain it, that instinct is worth a vet call.
Sign 3: Changes in Eating Habits
Most dogs are enthusiastic eaters, which is why a sudden disinterest in food tends to get noticed. But the subtler version — eating a little less, eating more slowly, or seeming less excited at mealtimes — often flies under the radar.
Nausea, dental pain, abdominal discomfort, and internal infections can all dampen appetite before other symptoms appear. On the flip side, a sudden increase in hunger can also signal something worth investigating, particularly in older dogs where it can point to diabetes or Cushing’s disease.
Tip: If your dog skips a meal, don’t panic. If it’s two or more in a row, or comes alongside other changes, it’s time to check in with your vet.
Sign 4: Unusual Discharge or Odour
Discharge from the eyes, nose, ears, or vulva isn’t always serious — but it’s always worth looking at more closely. A little eye goop in the morning is usually nothing. Persistent cloudy discharge, a strong or unfamiliar smell, or discharge that’s yellow, green, or blood-streaked is not.
For unspayed female dogs especially, any discharge from the vulva — particularly following a heat cycle — deserves prompt attention. It can be a warning sign of pyometra, which progresses quickly and can become life-threatening within days if left untreated. The closed form of pyometra shows no discharge at all, which makes the other signs on this list even more important to recognise.
Tip: Any unusual discharge in a female dog who hasn’t been spayed — especially 4–8 weeks after a heat cycle — warrants an urgent vet visit, not a wait-and-see approach.
Sign 5: Licking, Scratching, or Guarding a Specific Spot
Dogs will show you if they are uncomfortable with how they are being treated with their body. For instance, if your dog continually licks one of their paws, scratches at one of their ears, or seems uncomfortable with your touch in a specific area of their body, they are likely trying to tell you that something bothers them.
Licking at one area of the body over and over can be a sign of pain caused by an injury, infection, or allergy. Scratching at one of the ears can be a sign of an ear infection. Dogs will often flinch or get tense when you touch their belly if they are uncomfortable with having their belly touched. Paying attention to your dog’s body language is the only way they will tell you if they need your help.
Tip: Gently run your hands over your dog’s whole body every week or two. You’ll notice lumps, sore spots, or skin changes much earlier than if you only look.
The bottom line? You don’t need to be a vet to be a good advocate for your dog. You just need to know their normal — and pay attention when something shifts. Most of the time, it’s nothing. But catching something early can make all the difference.
When in doubt, call your vet. They’d rather hear from you once too often than not enough.
