Dog Illnesses & Diseases

Dog illnesses come in all shapes and sizes and with a multitude of symptoms.

If your puppy or dog gets sick it's worrying because he can't tell you how he feels (or what hurts) it can often be tricky to figure out what's wrong! 

Dog who is ill

To make matters worse, a young puppy, elderly or unvaccinated dog can get very sick, very quickly.

Many symptoms can be the same in the early stages of both minor AND major dog illnesses.

So it's hugely important to learn how to recognize the symptoms of various illnesses, diseases and conditions......... and to have a plan of action in place, just in case the worst happens.

Click on these links to jump straight to the info. you need, or scroll down to read it all:

Dog Illness Symptoms

There are a handful of symptoms of dog illnesses that crop up over and over again.

Sometimes they're a sign of something simple such as a tummy upset from last night's raid on the kitchen trash, but they can also be the early warning signs that a serious, even deadly, disease is taking hold.

Dog illness symptoms

If you're a first time dog owner it's almost impossible to know the difference, and even with years of experience 'under your belt' it's still very tricky.

I always tend to err on the side of caution and get a professional veterinary opinion if one of my 'babies' isn't feeling well and I'd strongly recommend that you do the same.

Taking a 'wait and see' approach MIGHT be okay, but it could literally cost Fido his life if he has something serious like Parvo. I definitely wouldn't advise taking the risk!

Here's a quick overview of the most common signs of dog illnesses: 

  • Loss of appetite
  • Lethargy or exhaustion
  • Fever (anything over 104F)
  • Shaking or tremors
  • Convulsions
  • Runny nose
  • Cough
  • Discharge from eyes
  • Sneezing
  • Swollen lymph nodes
  • Disorientation
  • Change in behavior

Here's a look at what some symptoms could mean.
Click on links to get more information on each disease....

Diarrhea - Vomiting - Lethargy - Fever

Canine Parvovirus





Runny nose - Eye discharge - Fever - Cough


Canine Hepatitis

Kennel Cough


Contagious Dog Illnesses

Canine Parvovirus:

Parvo is an extremely contagious viral disease that attacks the intestines, lymph nodes and bone marrow. Rarer variety can attack the heart resulting in sudden death.

Easily transmitted through contact with infected feces, either directly or on shoes, hands etc. Black and tan breeds such as Doberman Pinschers and Rottweilers tend to be especially vulnerable, as are Pitbulls.

Canine Parvo is probably the biggest threat to a young, unvaccinated puppy's health and one that claims the most lives during those early months.

Symptoms:  include extreme lethargy, loss of appetite, and severe vomiting and diarrhea (often bloody) which results in dehydration.

Treatment: is mainly supportive and relies heavily on intravenous fluids to counteract dehydration and intravenous antibiotics to attack sepsis infection.


Coccidiosis is one of the parasitic dog illnesses which affects the intestinal tract of puppies (most often seen in pups between 2 and 12 weeks of age).

Caused by the presence of the coccidian protozoa. Transmitted through feces. Many adult dogs and puppies are carriers of this disease but don't show symptoms and eventually build up an immunity to it.

If a young puppy is stressed, or unwell, this disease can 'flare up' as a result.

Symptoms:  include diarrhea, often pale grey to white in color and very smelly! Vomiting, lethargy and loss of appetite are common. These can be mild to severe.

Treatment:  is supportive, with fluids being given to combat dehydration. Plus the use of a sulfa-based anti-biotic to treat the disease, usually a 5 - 7 day course.

Canine Coronavirus:

Canine Coronavirus is a highly infectious viral disease that affects the intestines. Transmitted through feces.

Symptoms:  include diarrhea, lethargy, loss of appetite and dehydration.

Treatment:  is supportive and concentrates on treating the dehydration.

Canine Distemper:

Canine Distemper is a highly contagious viral disease. Can be transmitted through discharge from eyes or nose, through the air, or on shoes, hands etc.

Affects the lungs, intestines and central nervous system.

Symptoms:  include runny nose or eyes, coughing, vomiting and/or diarrhea, lethargy, loss of appetite. Can advance to include partial paralysis or seizures and behavioral problems.

Treatment:  is basically 'supportive care' such as encouragement to eat, fluid administration, antibiotics and veterinary care for seizures.


Giardia is another parasitic dog illness, also sometimes known as 'Beaver Fever'.

Caused by protozoa Parasites called Giardia, which are found in rivers, streams, lakes and other bodies of water that contain traces of animal feces.

Symptoms:  Many dogs with Giardia are 'a-symptomatic' which means that they don't show any symptoms, but continue to 'carry' and transmit the disease. However, the main symptom is diarrhea, which is often watery and foul-smelling. Vomiting, weight loss and lethargy may also occur.

Treatment:  antibiotics are required, and the most commonly used medications are Metronidazole (known as Flagyl) and Fenbendazole (Panacur). Both are effective, but your pup may need more than one round of treatment to eliminate the problem. Giardiosis can be transmitted to humans, so avoid swimming in water that could be infected, and follow excellent personal hygiene precautions if your dog gets this disease.


Highly contagious viral disease which affects the liver.

Starts in tonsils, spreads to lymph nodes, bloodstream and liver. Can be transmitted through urine, feces and saliva.

Symptoms:  are similar to Distemper. Severe cases can progress rapidly and cause sudden death.

Treatment:  is supportive care which may include IV fluids and medications.

Kennel Cough:

Canine Kennel Cough is a highly contagious bacterial and/or viral infection which affects the upper respiratory system. Transmitted through saliva or nasal discharge.

Symptoms:  a persistent hacking cough, sneezing, nasal discharge, sometimes fever.

Treatment : in mild cases can just be supportive, but in severe cases or when secondary infections are present (such as pneumonia) antibiotics are used.


Leptospirosis bacterial disease affecting the urinary system, including liver and kidneys. Mainly transmitted through infected urine.

Symptoms:  include loss of appetite, vomiting, lethargy, fever. More advanced symptoms include jaundice, increased thirst and dehydration due to frequent urination.

Treatment:  early antibiotic treatment can lessen the severity and/or duration of this illness.


Ringworm is a fungal infection (NOT worms) which affects the skin and hair.

Symptoms: circular patches of hair loss and red, inflamed or scaly skin. If left untreated these patches can eventually spread across the dogs' whole body.

Treatment: Medicated shampoos and dips. Sometimes oral medications are also prescribed.

Lyme Disease:

Lyme Disease is a bacterial infection that's transmitted to your dog through the bite of an infected deer tick.

Can affect the heart, kidneys and joints.

Symptoms:  include swollen and/or painful joints, limping, lethargy. A 'bullseye' type rash may appear at the site of the tick bite, but is unusual in canine lyme disease.

Treatment:  is usually several weeks on antibiotics


A highly infectious viral infection of the respiratory system. Easy airborne transmission through coughing and sneezing.

Symptoms:  include a runny nose, cough and fever.

Treatment:  is mostly supportive, with antibiotics being given for secondary infections.


One of the most well-known dog illnesses.

A severe and usually fatal viral disease that affects the brain and nervous system. Transmitted through saliva. Once symptoms appear this illness is always fatal to both dogs and humans.

Symptoms:  are behavioral and usually include unusual, irrational and frenzied aggression (if your dog was very shy you may see a increased affection or acute shyness if previously friendly). You may also see lack of co-ordination, seizures and the classic foaming at the mouth.

Treatment:  There is no treatment for Rabies and the disease is always fatal.

Non-Contagious Dog Illnesses & Conditions

Sometimes your pet can get sick without having 'caught' something.

There are too many possibilities to cover on just one page, but here are the most common dog illnesses that can cause your pup to be under the weather....


Dog allergies are pretty common and your pet can react to all sorts of things.

The most likely triggers are flea saliva, environmental/seasonal allergens (dust, mold, pollen etc.) and dog food ingredients.

Symptoms of allergies in dogs:

These are usually skin problems such as intense itching, relentless scratching, habitual licking (especially at the feet/legs/belly), red irritated and even inflamed areas of skin.

Irritated ears and constant scratching or head shaking are also common.

More info... Dog Allergy Symptoms

Treating dog allergies:

You can treat the irritation and itching of an allergy with antihistamines, any secondary infection (caused by scratching or licking) can be cured with antibiotics.

But in order to get rid of the allergy completely you need to find, and eliminate if possible, the 'trigger'.

More info... Dog Allergy Treatment


Hypoglycemia in dogs is caused by low blood sugar levels.

It's most common in small breeds, and especially in small breed puppies.

Symptoms of hypoglycemia in dogs:

These include weakness, disorientation, lack of co-ordination, shaking, severe lethargy, seizures, coma.

Canine Hypoglycemia can be fatal if left untreated.

Treating hypoglycemia:

The first and most important thing to do is to raise your dog's blood sugar level. 

A teaspoon of honey, Karo syrup or Haggen Dazs vanilla ice-cream given right away should help pretty quickly.

If your pup is in really bad shape rubbing the honey or syrup on his gums might help.

These tips should get your pup up and alert again, but you need to get him to a veterinarian for a check up urgently for further evaluation and to find out what caused the blood sugar drop.

If your pup is semi-conscious, unconscious or having seizures get him to an emergency vet immediately.

More info... Hypoglycemia in Dogs


These nasty parasites are transmitted by mosquitoes, and start out in your pet's bloodstream then migrate to his heart and other major organs.

Left untreated heartworm WILL cause heart failure and kill your dog.

Symptoms of heartworm in dogs:

These include lethargy, coughing, breathing difficulties, heart rhythm changes, and eventually collapse and death.

A Heartworm infestation takes about 6 months to show up and by the time it does your pet is already very sick indeed.

Prevention is absolutely critical in this illness, so make sure your puppy begins a monthly heartworm preventative as soon as you bring him home, and continue that throughout his lifetime.

Treating canine heartworm:

Treatment for a heartworm infestation is long, expensive and gruelling for your dog. It requires a lot of medication and complete rest.

Even then survival is not guaranteed.

More info on prevention and treatment... Heartworm

Intestinal Worms

When it comes to dog illnesses, worms might not seem like a big problem, and if treated early enough they usually aren't.

BUT, left untreated, a worm infestation can cause serious health issues, and could even kill your pet.

Symptoms of worms in dogs:

Some worms can be seen in your dog's stools, they may look like long thin pieces of spaghetti (roundworms), or like short fat grains of rice (tape worms) but others are not visible to the naked eye.

Diarrhea and vomiting are common symptoms of worms, and there may even be worms in your pet's vomit.

Other signs that of these parasites include a an underweight body with a distended belly, a dull dry coat, dull eyes, even a cough.

Treating canine worms:

You need to have your vet test a sample of feces from your puppy or dog so that he knows which type of worms are causing the trouble (and it could be more than one).

Then he will give, or prescribe, a safe and reliable dewormer to be given several times. This will get rid of all the worms in your pet's digestive tract.

More info... Puppy Worms

Puppy Strangles

Also known as Juvenile Cellulitis, Puppy Pyoderma, Sterile Granulomatous Dermatitis or Lymphadenitis.

Luckily it's not a very common condition.

An autoimmune disease which usually appears suddenly in puppies under 4 months of age. May have a hereditary component as some breeds are predisposed to developing it.

It needs to be treated quickly to avoid serious, or fatal, consequences.

Symptoms of Puppy Strangles:

These start off with generalized swelling of the puppy's face, but the most noticeable symptom is extreme swelling of the lymph nodes under the jaw and around the neck.

As this progresses it looks as though the puppy is being 'strangled' by the swelling, hence the name. Painful pimples and pustules then develop over the head/muzzle/ears.

Swelling might occur in other lymph nodes and joints, pustules may spread across the body, plus a puppy could lose his appetite and/or have a fever.

Treatment of Puppy Strangles:

Treatment usually consists of corticosteroids to reduce the swelling and inflammation, and antibiotics to kill off any secondary infection that has set up in the affected areas.

If your pup has a severe case, other treatments might be needed, or the standard treatment may need to be maintained for a longer period.


'Pano' is a condition that is most often seen in medium, large or giant breed puppies.

It's basically inflammation of the bones, usually in the front legs and it affects puppies between 6 and 18 months old.

It's a self-limiting disease which means that the majority of puppies will grow out of it without any treatment and without lasting side effects.

Most owners call it 'growing pains', and just accept it as a fact of life for many big puppies.

Experts haven't come to any real conclusion as to what causes this condition but it could be infection, hormones or diet.

Symptoms of Pano in puppies:

Usually a puppy with Panosteitis will have some pain in his legs, and will limp intermittently.

It's usually worse in the morning, after rest, or at the beginning of a walk or play session. Then the puppy 'walks it off' and seems fine.

Usually a pup will suffer on and off for 3 - 6 months and then recover. Occasionally it can be longer.

Occasionally a pup will have a fever, seem lethargic or lose his appetite as well. If this happens he needs to be seen by a vet because treatment might be needed.

Treating Pano in puppies:

Most puppies recover fully without treatment and Pano is just a nuisance, but if your pup has a lot of pain or other symptoms then your vet might prescribe corticosteroids or other anti-inflammatory medications to help him feel better.

More info... Panosteitis

Dog Bladder Infection

Canine bladder infections (aka Urinary Tract Infections or UTI's) are relatively common, considerably more so in female dogs than in males.

A bladder infection causes your dog a LOT of discomfort and increasingly frequent urination, plus other nasty symptoms.

Left untreated it can cause serious problems such as kidney infection and bladder stones.

Treating dog bladder infections:

A simple bladder infection is generally straightforward for your veterinarian diagnose and treat.

A course of the correct antibiotic can usually eradicate the bacteria responsible effectively.

But complications, simultaneous or resulting problems such as bladder stones (which can be life threatening) need a different sort of treatment.

More info... Dog Bladder Infection

Dog Eye Problems

Dog eye problems come in a whole host of different forms, and the symptoms of both minor and serious canine eye issues can be very similar.

Allergies, injury, physical malformation, infection and a number of diseases/conditions are all common triggers for eye problems in dogs.

Recognizing the signs of eye trouble and getting prompt veterinary attention for your dog if he has a problem is very important.

Untreated eye problems in dogs can lead to damaged vision, even blindness and should never be ignored.

Treating Dog Eye Problems

The treatment of eye issues depends entirely on what is causing the problem, and only a veterinarian can make an accurate diagnosis.

Options can include topical medications such as eye drops or salves and surgical procedures.

More info... Dog Eye Problems

Dog Ear Problems

Dog ear problems can be caused by infection, disease, parasites (such as ear mites), allergies and more.

Although they're often not serious/life-threatening, ear problems can make Fido very uncomfortable and even lead to other health conditions such as Vestibular Disease.

Chronic head-shaking, scratching at the ear area and discharge are common signs of dog ear problems.

Lumps, bumps or growths on the ear flap, or surrounding area, are also potential problems.

Treating Dog Ear problems:

Firstly it's important to get a veterinary evaluation of your dog's ears if he is showing signs of irritation, inflammation or discomfort.

Each condition will need a different type of treatment. Drops, wipes, ointment, oral medications or surgery are all possible treatment options depending on what is causing the problem.

More info... Dog Ear Problems

Dog Depression

Dogs are sensitive, emotional creatures and they can become depressed for a number of different reasons. 

Fido can't tell you he's feeling sad, despondent or depressed but you can learn to recognize the signs and get him the help he needs.

Treating Dog Depression:

There are lots of different treatment options, ranging from environmental and behavioral adjustments, natural remedies and prescribed medications.

Depression is a real medical condition and our dogs need help to bounce back.

More info... Dog Depression

Being able to recognize signs of a medical emergency in your dog could save his life.

This isn't always easy, but this page will help you figure out whether or not Fido's symptom/s require an immediate vet visit ..... Dog Emergency Symptoms

Prevention Is Key!

Having a sick pup is worrying, and getting him the care he needs to get better may be very expensive, so it makes sense to try to prevent your little guy or girl from getting sick in the first place.

Veterinarian with healthy terrier pup

Vaccinations are important when it comes to protecting Fido from certain contagious dog illnesses and diseases.

Regular deworming, monthly parasite prevention, a good nutritious diet and the right amount of exercise all help too.

Each breed has it's own weaknesses when it comes to health and many are predisposed to certain problems and conditions.

Some large and giant dogs are more at risk of catching contagious diseases such as Parvo, or inheriting a tendency to hip dysplasia or other orthopedic issues.

If you own a big dog, check out this page to learn more about the potential health issues he/she faces, and how to recognize and treat problems.... Big Dog Health Issues.

Of course, even with the best of care, accidents and unexpected illnesses can (and do!) happen.

Veterinary care isn't cheap, and if your dog needs surgery or extended care, you could be looking at a lot of money.

You can protect your pet, and your bank account, by getting pet dog insurance - this is basically health insurance for your pooch! It's not expensive, and can be a real life-saver if the worst happens.

Health Alert! New Canine Virus Update

There appears to be a livestock virus which has mutated to the point where it is a risk to our dogs.

Although only a handful of cases have been confirmed, researchers and veterinary professionals believe this it something all dog owners should be on the lookout for.

The virus is called CIRCOVIRUS and the main symptoms are bloody diarrhea, vomiting, lethargy, weakness & loss of appetite.

Of course, these symptoms are present in several different dog illnesses, and always warrant a vet visit asap.

But, it's important to make sure that your vet looks for underlying symptoms of Circovirus which include vasculitis, rapid heart rate and fluid on the lungs.

Quick diagnosis and prompt treatment give your dog the best chance of survival, so don't hesitate to push for an accurate diagnosis.

Also, no matter what the subject, I always think that a good reference book is worth it's weight in gold, and this is certainly true when you're talking about dog illnesses and other canine health issues.

Here are a few of the best dog health books available, you'll feel better if you have at least one of them on your bookshelf....

Related pages............

› Dog Illnesses

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