Top 10 Signs Your Dog May Be Sick (and What You Can Do)

Top 10 Signs Your Dog May Be Sick (and What You Can Do)

If your dog seems "off," it can be worrying. Because dogs can’t verbalise how they feel, it’s up to us as their caregivers to notice when something’s not right. Subtle changes in behaviour, appearance, and habits often indicate underlying health issues. Understanding these signs is key to catching illnesses early and getting your dog the care they need. Below, we’ll explore the top 10 signs your dog may be sick, why they happen, and what actions you can take to keep your furry friend healthy and happy.

1. Lethargy or Unusual Tiredness

Why it Happens

A sudden lack of energy is often a general indicator that something’s wrong. It could be a minor issue like recovery from a busy day of play, but it might also signal a serious condition like:

  • Infections: Viral or bacterial infections can cause fatigue as the immune system fights off the illness.
  • Anaemia: A lack of red blood cells reduces oxygen delivery to tissues, causing weakness.
  • Organ Problems: Diseases of the kidneys, liver, or heart often lead to lethargy.

What to Do

Observe how long the lethargy lasts. If your dog’s energy level doesn’t improve within 24 hours, or if it’s paired with other symptoms like vomiting or fever, consult a vet immediately. Meanwhile, make sure your dog has access to water and a quiet place to rest.

2. Changes in Appetite

Why it Happens

Appetite changes, whether an increase or decrease, often indicate an underlying issue:

  • Loss of Appetite: May result from GI problems, dental pain, stress, or serious illnesses like cancer.
  • Increased Appetite: Can be linked to diabetes, parasites, or conditions like Cushing’s disease.

What to Do

If your dog skips a meal, it’s not always cause for alarm. However, missing more than two meals in a row, or displaying ravenous hunger without a clear reason, requires a vet check. Gradual changes in appetite over weeks might also be worth noting during routine check-ups.

3. Vomiting or Diarrhoea

Why it Happens

Digestive upsets are one of the most common complaints in dogs. Causes include:

  • Dietary Indiscretion: Eating spoiled food or harmful substances.
  • Food Sensitivities: Intolerance to specific ingredients.
  • Infections or Parasites: Viral or bacterial infections like parvovirus or parasites like giardia.
  • Serious Illness: Organ dysfunction, toxins, or blockages.

What to Do

If your dog vomits or has diarrhoea once and seems otherwise fine, monitor them for improvement. Offer small sips of water to prevent dehydration and avoid food for 12–24 hours before reintroducing a bland diet (boiled chicken and rice).
Seek veterinary care if:

  • The symptoms persist beyond 24–48 hours.
  • There’s blood in the vomit or stool.
  • Your dog is lethargic or showing signs of pain.

4. Excessive Thirst or Urination

Why it Happens

Drinking more than usual or having more frequent accidents could be a sign of:

  • Kidney Disease: The kidneys can’t concentrate urine properly, leading to increased thirst.
  • Diabetes: High blood sugar levels increase water loss in urine.
  • Urinary Tract Infections: Irritation causes frequent urination.

What to Do

Monitor your dog’s water intake and note if they’re urinating more often or in unusual places. Take your dog to the vet for blood and urine tests to identify the underlying issue.

5. Coughing or Breathing Changes

Why it Happens

Coughing and breathing difficulties often point to respiratory or cardiac issues, such as:

  • Kennel Cough: A contagious condition common in dogs exposed to other animals.
  • Heartworm Disease: A parasitic infection that affects lung function.
  • Pneumonia or Asthma: Infections or allergies can inflame the airways.

What to Do

Any significant breathing changes—especially laboured or noisy breathing—should be treated as an emergency. Persistent coughing should also be evaluated by a vet to rule out serious conditions.

6. Skin Irritations or Hair Loss

Why it Happens

Itchy skin, rashes, or bald patches might stem from:

  • Allergies: Environmental or food-related.
  • Parasites: Fleas, mites, or lice.
  • Hormonal Imbalances: Conditions like hypothyroidism or Cushing’s disease.

What to Do

Inspect the affected area for redness, scabs, or swelling. Use a flea comb to check for pests. For severe or persistent skin issues, consult your vet. If food allergies are suspected, consider My Pet Sensitivity’s dog food intolerance test for a deeper understanding of triggers.

7. Bad Breath or Excessive Drooling

Why it Happens

Oral health plays a significant role in overall health, and issues such as:

  • Dental Disease: Tartar build-up, gum infections, or abscesses.
  • Liver or Kidney Disease: Metabolic by-products can cause bad breath.
  • Foreign Objects: Items lodged in the mouth or throat might increase drooling.

What to Do

Regularly brush your dog’s teeth and schedule annual cleanings. If bad breath or drooling is sudden or severe, a vet visit is necessary to check for dental disease or systemic issues.

8. Changes in Weight

Why it Happens

  • Weight Loss: May indicate worms, cancer, or metabolic disorders like diabetes.
  • Weight Gain: Often linked to hypothyroidism, overfeeding, or lack of exercise.

What to Do

Weigh your dog monthly and monitor for fluctuations. Gradual weight changes aren’t always obvious, so look for signs like a thinner coat or trouble climbing stairs. If you notice unexpected changes, consult your vet for diagnostic testing.

9. Behavioural Changes

Why it Happens

Changes in temperament or habits can result from:

  • Pain or Illness: Discomfort can make dogs aggressive or withdrawn.
  • Neurological Issues: Problems like seizures or cognitive dysfunction can alter behaviour.
  • Stress or Anxiety: Life changes or trauma may lead to clinginess or fearfulness.

What to Do

Observe patterns and context—does your dog react poorly to specific triggers? If the behaviour shift seems unrelated to external factors, seek veterinary advice to rule out pain or illness.

10. Limping or Difficulty Moving

Why it Happens

Mobility issues could indicate:

  • Injuries: Sprains, fractures, or cuts on the paws.
  • Arthritis: Common in older dogs and certain breeds.
  • Neurological Problems: Conditions like slipped discs can cause weakness or paralysis.

What to Do

Rest your dog and limit physical activity. Inspect their paws for cuts, swelling, or foreign objects. Persistent limping or difficulty moving requires immediate veterinary attention.

When to See a Vet

You should see a vet if:

  • Symptoms are severe or worsening.
  • Multiple symptoms occur simultaneously (e.g., vomiting and lethargy).
  • The issue persists for more than 48 hours without improvement.

How to Keep Your Dog Healthy

1. Feed a Balanced Diet

Provide high-quality dog food tailored to your dog’s age, size, and health needs.

2. Stay on Top of Preventatives

Administer parasite preventatives regularly and schedule vaccinations.

3. Monitor Behaviour

Catch changes early by paying attention to your dog’s habits, energy levels, and appetite.

4. Routine Vet Visits

Annual check-ups can identify issues before they become severe.

5. Consider Allergy Testing

If your dog suffers from chronic skin issues, digestive problems, or unexplained illnesses, My Pet Sensitivity’s dog food intolerance test can help uncover triggers and guide you towards better choices.

Conclusion

Your dog’s health is your responsibility, and recognising these signs early can make a significant difference in their well-being. From changes in appetite to behavioural shifts, knowing what to watch for empowers you to act quickly. If you suspect food intolerances or allergies, we offer a simple allergy test to help you optimize your dog’s diet and keep them thriving. Always consult your vet when in doubt—your dog deserves nothing less than the best care.

To provide you with technically accurate evidence-based information, content on the MyPetHealthStore blog is reviewed by medical professionals with veterinary expertise.

This article was reviewed by:

Hannah Shepherd RVN
Qualified Registered Veterinary Nurse & BVNA Member