How to Spot Early Signs of Illness in Dogs

It is distressing when your pet is under the weather, but it isn’t always easy to spot signs of illness in dogs. Sometimes ill pets appear to be in normal health, so there are some obvious and more subtle things that you need to look out for.

Equally, if your dog has any symptoms it doesn’t necessarily mean your pet is ill, and only a veterinary diagnosis can determine the cause.

Read on to learn more about the most common symptoms of illness in dogs, and advice for when to take action.

In this article:

1. Vomiting and Diarrhoea
2. Temperament and Behavioural Changes
3. Vocal Signals
4. Urination and Thirst
5. Changes in Appetite or Weight
6. Skin and Coat
7. Joints and Stiffness
8. Eye, Mouth and Nose Symptoms
9. Breathing and Respiratory Issues
10. Emergency Warning Signs
11. When to Worry About a Sick Dog

Vomiting and diarrhoea

Regular vomiting and diarrhoea are signs that your dog could be unwell. An animal may vomit for many reasons other than being ill, such as if they have swallowed something they shouldn’t have. This is usually nothing to worry about, but is a concern if it is happening repeatedly.

There are many reasons why your dog could vomit, including bacterial infections and pancreatitis. Addressing it immediately rules out anything more serious. Consult a vet as soon as possible if you notice any blood in the vomit, urine or stools as it could indicate gastric ulcers or a number of other conditions. 

Diarrhoea could be the result of a change in diet, an allergic reaction or stress, or something more serious such as kidney or liver disease.

You should also contact your vet immediately if your dog vomits or has diarrhoea more than once in 24 hours to avoid complications like dehydration. 

Temperament and behavioural changes

A change in temperament could also mean your dog is feeling sick, for instance, if they switch from a friendly pet that loves company to being irritable and isolated. Your dog could be stressed or reacting to a change in the home, or something could be making them unhappy.

The following behaviours can also sometimes be a symptom of illness in dogs:

• Panting
• Excessive lip licking
• Sudden aggression or irritability
• Increased clinginess or attention-seeking
• Obsessive behaviours (e.g. tail chasing, pacing)
• Lethargy or lack of activity

If your usually active dog seems to be spending more time lying down instead of playing with you, there will be a reason. Lethargy can be a sign of mental as well as physical illness, brought on if your dog has suffered some form of trauma. Symptoms like loss of balance, staggering, apparent confusion or disorientation can also indicate a neurological issue, and should be taken seriously. 

Vocal signals

A dog’s inability to tell their owners exactly how they feel can often be vocalised in other ways.

If your dog whines, whimpers, cries or barks more frequently, or at unusual times of the day, they could be trying to tell you they are ill or in pain. Barking may also indicate a behavioural condition in your dog, or could be due to age, such as if your senior pet is going deaf. 

Urination and thirst

Another sign that something isn’t right is your dog urinating more or less frequently than usual.

If your pet’s thirst has increased significantly on top of this, your dog could have diabetes. Frequent urination can also indicate liver or kidney disease.

If your housetrained dog is urinating in areas they know they shouldn’t, not urinating as often or straining, this could mean kidney stones, kidney disease or a problem with the urinary tract.

Changes in appetite or weight

Sudden weight gain or loss can be another sign of sickness in your dog. Watch out for weight fluctuations or any differences in your pet’s appetite (for example, refusing food without explanation). There may just be a minor problem with your dog such as an infection, but always visit the vet to rule out anything more serious, such as diabetes, thyroid problems, or digestive disorders.

Weight loss or gain, as well as bad breath, can also be a sign of dental problems or gum disease, digestive or respiratory problems, as well as many other ailments. Ensure you take your dog to the vet if any fluctuations in weight or appetite occur so you can get a full diagnosis.

Skin and coat

A dull coat or any skin problems also need to be addressed. Look for signs such as dandruff and sore patches that indicate sensitive skin, but could also mean an underlying issue. Watch out for any behavioural changes such as chewing of the skin as well.

If your dog is scratching or licking their coat excessively or losing hair in patches, it's important to consult your vet as this could be a reaction to parasites like fleas and ticks, or conditions like mange. 

Joints and stiffness

Although stiffness in older dogs is not unusual, it still needs to be investigated by a vet to determine the cause. Arthritis is common in older dogs but it’s not always the cause of stiffness joint problems.

You should also consult your vet right away if any joint-related symptoms are affecting a young dog. These can include limping or difficulty standing, any changes in gait or posture, and reluctance to go upstairs or for walks. 

Eye, mouth and nose symptoms

Symptoms affecting your dog’s eyes, mouth, or nose can also be signs your dog is not feeling well. Watch out for:

• Redness or inflammation in the eyes
• Excessive blinking, squinting, or pawing at the face
• Discharge from the eyes (clear, yellow, or green)
• Runny nose or nasal discharge (yellow/green)
• Bad breath or swollen, red, bleeding gums
• Yellow/brown plaque build-up or difficulty chewing
• Loose teeth or pain while eating
• These symptoms may indicate conditions in your pooch including infections, allergies, or dental disease, so it’s important to arrange a vet visit if you’re concerned. 

Breathing and respiratory issues

Breathing changes are among the most serious dog sickness symptoms. Fast or shallow breathing, excessive panting, or a persistent cough can indicate illness ranging from infections like kennel cough to heart or lung problems.

Key symptoms to look out for include:

• Excessive panting (even at rest)
• Rapid or shallow breathing
• Persistent coughing or wheezing
• Nasal discharge or sneezing
• Bluish tint to the gums or tongue
• Laboured breathing or difficulty catching breath

If your dog shows these signs of illness, get veterinary help straight away.

Emergency warning signs

The following symptoms indicate a serious problem that requires emergency veterinary care:

• Difficulty breathing or excessive panting
• Seizures or collapse
• Swollen abdomen or bloated appearance
• Severe lethargy (unable to move or respond)
• Blood in vomit, stools, or urine
• Excessive bleeding or trauma
• Sudden inability to walk or stand
• Intense abdominal pain or bloating

If you notice any of these signs, get your dog to your nearest veterinary practice immediately.

When to worry about a sick dog

Dogs are masters at masking pain and discomfort, so even minor ailments could be a signal that something more serious is brewing. If they’re showing subtle signs of sickness like a change in behaviour or appetite, monitor their symptoms closely for any changes over a couple of days before taking action. For more serious symptoms like difficulty standing or breathing, it’s important to get help right away.

At the end of the day, you know your pooch best. If something feels off, or if you’re ever in doubt, it’s always best to book a vet appointment. Your vet can perform a thorough check-up and provide clarity, ensuring that any potential issues are addressed early. 

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