Is Your Dog Running a Fever? What to Do and When to Call the Vet

When your dog seems off, quieter than usual, less interested in their favorite toy, or just not quite themselves, it’s natural to wonder if something is wrong. Fever in dogs is one of the most common signs that your pet’s body is fighting something, and it’s also one of the most misunderstood. Unlike humans, dogs can’t tell us they feel warm or achy, which means it falls on you to recognize the signs of a dog fever before the situation escalates. The good news? Once you know what to look for, you can act quickly and confidently and this guide will walk you through everything you need to know.

What Is a Normal Body Temperature for Dogs?

Understanding what’s normal is the first step in identifying fever in dogs. A healthy dog’s body temperature typically ranges between 101°F and 102.5°F (38.3°C to 39.2°C), which is naturally higher than the average human body temperature of 98.6°F. When a dog’s temperature rises above 103°F, it is generally considered a fever, and anything above 104°F warrants immediate veterinary attention.

Many pet owners are surprised to learn that their dog runs warmer than they do. This is entirely normal canine physiology. It’s important to have a baseline sense of your dog’s typical temperature so you can more accurately identify when something has shifted. A rectal thermometer is the most reliable way to take a dog’s temperature at home, though this should always be done carefully and calmly to avoid stressing your pet.

Common Causes of Fever in Dogs

A fever is not a diagnosis. It’s a symptom, and it can point to a wide range of underlying conditions. Some causes are relatively minor, while others are serious and require prompt medical care. Regardless of the suspected cause, a fever that persists for more than 24 hours or reaches 104°F or above should always be evaluated by a veterinary professional. The following are among the most frequently seen triggers for dog fever.

Infections (Bacterial, Viral, or Fungal)

Infections are the leading cause of fever in dogs. Bacterial infections such as leptospirosis, tick-borne illnesses like Rocky Mountain spotted fever or ehrlichiosis, and upper respiratory infections can all cause a dog’s temperature to spike. Viral infections including parvovirus and distemper are serious and often accompanied by other symptoms such as vomiting, diarrhea, or coughing.

Fungal infections, while less common, can also trigger fever, particularly in dogs who spend time outdoors. Your veterinarian will often run bloodwork or other diagnostic tests to identify the specific pathogen involved before recommending treatment. Early detection of an infection is critical to a faster and more complete recovery.

Vaccinations

It is not uncommon for dogs to develop a mild, low-grade fever in the 24 to 48 hours following a vaccination. This is actually a sign that the immune system is responding to the vaccine and building protection which is exactly what the vaccine is designed to do. Post-vaccination fever is typically mild and self-limiting, resolving on its own within a day or two.

However, if your dog’s fever following a vaccination exceeds 103°F, persists longer than 48 hours, or is accompanied by swelling, difficulty breathing, or extreme lethargy, contact your veterinarian promptly. Keeping a record of your dog’s vaccination dates and any reactions helps your vet track patterns and adjust future care accordingly. Never assume post-vaccine symptoms are harmless without professional guidance.

Ingestion of Toxins

Dogs are curious creatures, and they sometimes eat things they shouldn’t. Ingesting certain toxins including toxic plants, human medications, xylitol (an artificial sweetener found in many foods), or rat poison can cause a dangerous rise in body temperature. Toxic ingestion is a veterinary emergency and should be treated as such, regardless of how small the amount ingested appears to be.

If you suspect your dog has eaten something toxic and is displaying a fever alongside vomiting, tremors, or unusual behavior, go to an emergency vet immediately. Time is a critical factor when toxins are involved, and early intervention dramatically improves outcomes. Do not wait for symptoms to worsen before seeking care.

Inflammatory Conditions and Immune Disorders

Some dogs develop fevers as a result of inflammatory or immune-mediated conditions, such as lupus or inflammatory bowel disease. In these cases, the body’s immune system is essentially overreacting, and fever can be one of the ongoing symptoms. These conditions are more complex to diagnose and manage, and they often require a combination of bloodwork, imaging, and specialist input.

If your dog has a recurring or unexplained fever (sometimes called a fever of unknown origin in dogs), your veterinarian may recommend a more in-depth diagnostic workup. Chronic fever in dogs should never be dismissed as “just stress” or a temporary bug. Persistent or recurrent fever is always worth investigating thoroughly.

Signs and Symptoms of Fever in Dogs

Because dogs can’t verbally communicate discomfort, tuning into behavioral and physical cues is essential. Many of the signs of a dog running a fever overlap with general signs of illness, but there are specific indicators that suggest elevated body temperature. Recognizing these early gives you the best opportunity to seek timely veterinary care and prevent the condition from progressing. Keep in mind that a dog’s nose being warm or dry is a popular myth and this alone is not a reliable indicator of fever. The following are the most common and recognizable symptoms of dog fever to watch for.

• Lethargy or unusual tiredness: A feverish dog often loses interest in play, walks, or activities they normally enjoy.
• Loss of appetite: Fever commonly causes dogs to skip meals or show little enthusiasm for food or water.
• Shivering or shaking: Even when a dog’s body temperature is elevated, they may shiver as the fever sets in.
• Warm ears or paws: While not definitive, notably warm ears or paw pads can be a supporting indicator of fever.
• Red or glassy eyes: Bloodshot, watery, or glassy-looking eyes often accompany an elevated temperature.
• Nasal discharge: A runny nose, especially alongside other symptoms, may point to an infectious cause of fever.
• Coughing or vomiting: These symptoms alongside fever may suggest a more serious underlying condition requiring prompt care.

How to Take Your Dog’s Temperature Safely

If you notice multiple symptoms of dog fever, taking your pet’s temperature before calling the vet can help provide useful information. The most accurate method is a rectal reading using a digital thermometer designed for pets. Apply a small amount of pet-safe lubricant to the thermometer tip, gently lift your dog’s tail, and insert the thermometer about one inch into the rectum, holding it in place until it beeps.

This process is easier with a second person to help keep your dog calm and still. Ear thermometers designed for veterinary use are also available and may be more comfortable for some pets, though they can be slightly less accurate. Always sanitize the thermometer thoroughly before and after use, and label it clearly so it is never confused with a thermometer used for humans.

When to Call the Vet for Dog Fever

Knowing when dog fever requires veterinary attention can be the difference between a manageable situation and a medical emergency. As a general rule, any dog with a temperature above 103°F should be seen by a veterinarian, and a reading of 104°F or higher is an emergency. But temperature alone doesn’t tell the whole story as the accompanying symptoms matter just as much. A dog with a mild fever of 103°F who is alert, drinking water, and behaving relatively normally is in a different category than a dog with the same temperature who is limp, vomiting, or unable to stand. Always err on the side of caution when it comes to your pet’s health, because acting early almost always leads to better outcomes. If you’re unsure, call Pets Furst Urgent Care at (215) 755-1000. We can help you assess the severity of the situation over the phone and advise you on next steps.

Signs That Require Emergency Veterinary Care

Certain symptoms alongside a fever are red flags that require immediate emergency veterinary care, not a scheduled appointment. These include seizures, difficulty breathing, collapse, uncontrollable vomiting or diarrhea, suspected toxin ingestion, severe pain, or a fever above 106°F. A temperature this high can cause damage to internal organs, neurological impairment, and in extreme cases, death. Pets Furst Urgent Care is equipped to stabilize your pet quickly and run diagnostics that a standard appointment may not accommodate. Do not wait until morning if your dog is showing these signs, seek emergency care right away. Your pet’s life may depend on the speed at which you act.

What Your Vet Will Do to Diagnose and Treat Dog Fever

When you bring your dog in to Pets Furst Urgent Care for a fever, we will begin with a thorough physical examination to assess your dog’s overall condition. We will take a rectal temperature, examine the lymph nodes, listen to the heart and lungs, and check for any external signs of infection or injury. From there, diagnostic testing including bloodwork, urinalysis, and potentially X-rays or ultrasound may be recommended to identify the underlying cause.

Treatment depends entirely on the root cause: bacterial infections may be treated with antibiotics, while inflammatory conditions might require anti-inflammatory medications or immunosuppressive therapy. Your vet may also recommend supportive care such as IV fluids to maintain hydration, especially in cases where the dog is not drinking adequately. Following through with the full course of prescribed treatment and attending any recommended follow-up appointments is essential for a full recovery.

Book Your Dog’s Appointment for Expert Care

Fever in dogs is a signal that something in the body needs attention, and the sooner it’s addressed, the better the outcome for your pet. Whether your dog’s temperature is mildly elevated or dangerously high, the veterinary team at Pets First Urgent Care is here to help you navigate the situation with compassion and expertise. We offer urgent and same-day appointments for pets who need prompt evaluation, and our team is trained to diagnose and treat a wide range of conditions that cause fever in dogs. If your dog is showing signs of fever, call us at (215) 755-1000 today. Your dog counts on you to take action, and we’re here to make sure that action leads to the care they need.