When your dog has a fever and stops eating, it’s a sign that their body is fighting something serious. Fever in dogs isn’t a condition itself but a symptom pointing to infection, inflammation, or illness.
We outline the common causes of dog fever and not eating, what you can do at home, and when to seek veterinary help.
Dog Fever and Not Eating — Why It Happens
Dogs with a fever often stop eating because their body is focusing its energy on fighting off an illness or infection.
A fever in dogs can come from many sources — from something as common as a respiratory infection to more complex issues like immune disorders or tick-borne diseases.
This rise in temperature can make dogs lethargic, uncomfortable, and less interested in food. The loss of appetite is the body’s natural way of conserving energy for healing.
Common Causes of Dog Fever and Not Eating
Infections (Bacterial or Viral)
One of the most common reasons for a dog to have a fever and stop eating is an infection.
Upper respiratory infections, abscesses, urinary tract infections, and gastrointestinal infections can all trigger fever.
As your dog’s immune system ramps up to fight off pathogens, their appetite typically decreases. Additional symptoms like coughing, nasal discharge, vomiting, or diarrhea may appear depending on the type of infection.
Tick-Borne Diseases
Tick-borne illnesses such as Lyme disease, ehrlichiosis, and anaplasmosis are known to cause fever and appetite loss.
If your dog has recently been in a grassy or wooded area, and now has a fever and is refusing food, tick-related illnesses could be the culprit. These diseases often cause other symptoms like joint pain, lethargy, and swollen lymph nodes.
Prompt diagnosis and treatment are key to preventing long-term complications.
Read more: Dog Fatigue and Not Eating (Understand what’s behind it)
Immune-Mediated Diseases
Conditions like Immune-Mediated Hemolytic Anemia (IMHA) or Lupus (SLE) can cause the immune system to attack the body’s own cells.
These conditions often trigger persistent fever, fatigue, and anorexia (loss of appetite). Owners may also notice pale gums, weakness, or unexplained bruising.
These are life-threatening and require urgent veterinary care.
Inflammatory Conditions
Diseases that cause inflammation — such as pancreatitis or inflammatory bowel disease (IBD) — often lead to fever and a disinterest in food.
Pancreatitis, in particular, causes abdominal pain and vomiting, and dogs with this condition may refuse food for days. You may also notice a hunched posture or signs of abdominal discomfort.
These issues need professional care to manage inflammation and prevent further organ damage.
Cancer
Fever and anorexia can also point to more serious systemic illnesses like cancer.
Tumors, especially if they affect internal organs, can lead to infection, inflammation, and immune suppression — all of which contribute to a rise in body temperature and reduced appetite.
Weight loss, persistent vomiting, or visible masses may accompany these signs.
Recent Vaccination
Some dogs develop a low-grade fever and temporary appetite loss after receiving vaccines.
This is generally mild and resolves within 24–48 hours. However, if your dog seems unusually tired or skips more than one meal, it’s worth discussing with your vet to rule out a more severe reaction.
What to Do If Your Dog Has Fever and Is Not Eating
Start by checking your dog’s temperature with a rectal thermometer. A normal temperature is between 101°F and 102.5°F (38.3°C–39.2°C). Anything above 103°F (39.4°C) is considered a fever.
Encourage rest and provide fresh water to prevent dehydration. You can offer bland food such as plain chicken and rice if they seem interested in eating again.
Avoid giving over-the-counter medications like ibuprofen or acetaminophen, as these are toxic to dogs.
Keep your dog in a cool, calm environment and avoid physical activity until the fever subsides or you receive veterinary guidance.
Always monitor for other symptoms like vomiting, coughing, diarrhea, or signs of pain. These can give more clues to the underlying cause.
When to Call or Visit Your Vet
If your dog’s fever exceeds 103.5°F (39.7°C), or if they go more than 24 hours without eating, seek veterinary attention immediately.
You should also contact your vet if:
The fever lasts more than a day.
They’re vomiting or have diarrhea.
They show signs of pain or swelling.
They’re lethargic or hiding.
You notice pale gums or labored breathing.
Some causes of fever are life-threatening if not treated promptly, and early intervention leads to better outcomes.
Read more: Dog Shaking and Not Eating (Why it might be serious)
Key Takeaway
If your dog has a fever and isn’t eating, it’s a sign that their body is under stress from illness, infection, or inflammation.
While some cases are mild and self-resolving, others need prompt veterinary care to prevent serious complications.
Watch your dog closely, keep them hydrated and rested, and don’t hesitate to reach out to your vet if you’re unsure.
Your attention and quick action can make a big difference in their recovery.