What this means
Owners often feel a dog's nose or ears, but warm ears or a dry nose say almost nothing about a fever. Only a thermometer measures temperature reliably, and this is usually done at the vet's clinic. At home it is better to watch for other signs: your dog is lethargic, eats less, shivers, breathes heavily or hides.
It matters to tell a fever from overheating. A dog who has been in a hot car or in the sun, or who worked hard in hot weather, may be overheated by the surroundings rather than ill. Such a dog pants hard, drools heavily and can become weak. That is an urgent situation, not one that can wait.
When a dog has a fever with no obvious outside reason, the search is for a focus of inflammation or infection: in the skin, mouth, ears, urinary tract or elsewhere. In some cases a fever keeps returning without an infection, for example from an immune system disorder or a condition particular to certain breeds. Write down when your dog became lethargic and which other changes came with it.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your dog.
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Overheating
Heat, a closed car or hard exertion in hot weather can raise the temperature without any illness. The dog pants fast, drools heavily and grows weak.
About the condition: Overheating (heat stroke) -
Infection or inflammation
The body raises its temperature to fight an infection, for example in a wound, the teeth, the ears or the urinary tract. Lethargy and a smaller appetite go with it.
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Skin infections
A deeper skin infection or an abscess can cause a fever. The skin may be red, painful, warm to touch or moist.
About the condition: Skin infections -
Immune system disorders
When the immune system acts against the body's own tissues, a fever can return without a clear infection. The dog may be lethargic and may have sore joints.
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Shar-pei fever
Shar-peis can have a condition of periodically recurring fever, sometimes with swollen hock joints. It is only identified once a vet has ruled out other causes.
About the condition: Familial Shar-Pei fever (recurrent fever)
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Whether your dog is more lethargic or eats less
- Whether there is shivering or a wish to hide
- Whether there was hot weather, a closed car or heavy exertion
- Whether there is a swelling, wound or sore spot
- Whether there is vomiting, diarrhoea or coughing
- Whether the fever keeps coming back
When to book a routine visit
Book a visit if your dog is lethargic and you suspect a fever, if it keeps returning or lasts more than a day. If your dog has overheated, struggles to breathe or collapses, go straight away.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Overheating (heat stroke) General health Overheating is a condition in which a dog's body temperature rises to a dangerous level because it can no longer cool itself down. Dogs barely sweat and cool themselves by panting, so heat in a closed car or exercise on a hot or humid day can overwhelm them quickly. Heat stroke damages the internal organs and is life-threatening, so the dog needs a vet immediately.
- Autoimmune disorders Blood and immunity This is an umbrella term for conditions in which the immune system, instead of defending the body against germs, starts attacking the dog's own tissues. The skin, blood cells, joints or internal organs can be affected, so these diseases can look very different from one another. What the condition is and what caused it is for the vet to determine.
- Familial Shar-Pei fever (recurrent fever) Blood and immunity This is an inherited inflammatory disorder in which a dog has repeated bouts of fever for no obvious reason, sometimes together with swollen joints. The bouts pass on their own, but the repeated inflammation can, over time, be linked to protein deposits building up in organs, the kidneys in particular. Any fever can also have other causes, so a dog with a fever needs to see a vet.
- Skin infections Skin and coat Skin infections are caused by bacteria or yeast that start to multiply when the skin's defences are weakened, for example by an allergy, parasites, moisture trapped in skin folds or constant scratching. An infection can stay on the surface or reach the deeper layers of the skin, causing pain and intense itching. What caused the infection and what keeps it going is for a vet to work out.
- Parvovirus Infections Parvovirus is a highly contagious viral disease of dogs that damages the lining of the gut and the blood cells that defend the body against infection. Puppies and unvaccinated dogs are at greatest risk. The illness moves fast and the dog loses a great deal of fluid, so it needs a vet immediately.
- Distemper Infections Distemper is a contagious viral disease that can damage the airways, the digestive system, the skin and the nervous system. Puppies and unvaccinated dogs are at greatest risk. What is making a dog ill and how far the disease has gone is for a vet to work out, and the first signs are easily mistaken for an ordinary cold.
- Leptospirosis Infections Leptospirosis is a bacterial infection that a dog catches from water, damp ground or objects contaminated with the urine of infected animals, especially rodents. The bacteria damage the kidneys and liver, and the illness can quickly become life-threatening, so the dog needs a vet immediately. Leptospirosis also passes to people.
- Babesiosis Parasites Babesiosis is a tick-borne disease caused by microscopic parasites that settle in the red blood cells and destroy them. In Lithuania it is spread by the ornate dog tick, so it is worth every dog owner knowing about. It can become life-threatening within days, so the dog needs a vet immediately.
- Lyme disease Infections Lyme disease is a bacterial infection passed to a dog by an attached tick. In Lithuania its bacteria are spread by the castor bean tick, which lives in woods, parks and long grass. Some infected dogs show no signs at all, while others develop painful joints weeks or months later; whether this disease is behind a dog's illness is for a vet to establish.
- Anaplasmosis Infections Anaplasmosis is a tick-borne bacterial infection whose bacteria settle inside white blood cells. In Lithuania it is spread, like Lyme disease, by the castor bean tick. Some infected dogs show no signs, while others develop a fever and a limp within a few weeks of the tick bite; what caused the illness is for a vet to establish.
- Pyometra General health Pyometra is a pus-filled infection of the womb that can develop in an unspayed bitch in the weeks after a season. Pus collects in the womb, and substances released by the bacteria harm the whole body. The condition can quickly become life-threatening, so the bitch needs a vet immediately.
Body systems: General health Blood and immunity Skin and coat Infections Parasites