Dog Fever: Symptoms, Causes, and How to Treat It

When your dog is not acting like themselves, it is natural to worry. A fever can be one of the body’s ways of fighting infection, but it can also signal something more serious that needs prompt veterinary care. In this guide, I will walk you through what dog fever is, how to spot it at home, common causes, and what to do next so you can make calm, informed decisions.

What counts as a fever in dogs?

A dog’s normal body temperature is higher than a human’s. Most healthy dogs run around 101°F to 102.5°F (38.3°C to 39.2°C). In general, a temperature of 103°F (39.4°C) or higher is considered a fever.

Temperatures around 104°F (40°C) or higher can become serious quickly, especially if they persist, your dog is very ill, or the elevation is due to hyperthermia

The most accurate way to check

The only reliable way to confirm a fever at home is with a thermometer, typically a rectal digital thermometer designed for pets. Ear thermometers can be less reliable if placement is off or if there is ear inflammation, although some veterinary-grade aural thermometers can be accurate when used correctly.

• Use lubrication (pet-safe or water-based).
• Have help if possible to gently hold your dog steady.
• Reward afterward with calm praise or a small treat.

If you cannot safely take your dog’s temperature, do not force it. Focus on symptoms and call your veterinarian.

Fever vs heat stroke

Pet parents often use “fever” to describe any high temperature, but there are two different situations. A true fever happens when the body intentionally raises its temperature set-point, usually due to infection or inflammation. Hyperthermia

Dog fever symptoms to watch for

Many dogs with fever look generally “off.” Some signs are subtle, especially early on.

• Lethargy or unusually low energy
• Warm ears or paws (not diagnostic, but can be a clue)
• Shivering or trembling
• Loss of appetite
• Increased thirst or sometimes decreased drinking
• Panting at rest (especially without heat or exertion)
• Nasal discharge or coughing
• Vomiting or diarrhea
• Stiffness, reluctance to move, or signs of pain
• Red eyes or general discomfort

Important note: A dry nose does not reliably indicate fever. Nose moisture varies for many normal reasons.

Once you spot symptoms, the next step is thinking about likely causes and how urgently your dog needs care.

Common causes of fever in dogs

Fever is a symptom, not a diagnosis. The “why” matters because treatment depends on the underlying cause.

1) Infection

This is one of the most common reasons.

• Viral infections (for example, canine influenza)
• Bacterial infections (skin infections, pneumonia, urinary tract infections)
• Tick-borne diseases (such as ehrlichiosis, anaplasmosis, Lyme disease depending on region)
• Dental disease or tooth root infections
• Wound infections or abscesses

2) Inflammation or immune-related disease

Some dogs develop fever from inflammatory conditions where the immune system is overactive.

• Immune-mediated diseases
• Pancreatitis
• Inflammatory bowel disease flares
• Joint inflammation

3) Heat-related illness

Heat exhaustion and heat stroke can cause dangerously high temperatures. This is not the same as a typical fever, but it can look similar at first.

• Risk increases with hot weather, humidity, brachycephalic breeds, and poor ventilation.

4) Toxins and medication reactions

Some toxins or adverse drug reactions can trigger fever and systemic illness.

• Ingestion of toxic foods, plants, or chemicals
• Reactions to certain medications

5) Recent vaccination

Some dogs can have a mild, short-lived fever or low energy after vaccines. This should improve within a day or so. If your dog seems very unwell, the fever is high, or symptoms last longer than expected, contact your veterinarian.

6) Fever of unknown origin

Sometimes a fever persists and initial testing does not reveal an obvious cause. Your veterinarian may recommend additional labs, imaging, or referral depending on the situation.

What to do at home

Think of home care as supportive care while you get professional guidance. The goal is to keep your dog safe and comfortable, not to “treat” the fever without knowing the cause.

Do

• Call your veterinarian, especially if symptoms are significant or your dog is very young, elderly, pregnant, or immunocompromised.
• Offer fresh water and encourage gentle drinking to reduce dehydration risk.
• Keep them cool and calm in a well-ventilated room, away from heavy blankets.
• Monitor symptoms: appetite, energy, vomiting, diarrhea, coughing, urination, and gum color.
• Check temperature if it can be done safely.

Do not

• Do not give human fever reducers like ibuprofen, acetaminophen (Tylenol), or aspirin unless your veterinarian specifically instructs you to. These can be dangerous or toxic to dogs, and even medications that are sometimes used in dogs (like aspirin) should never be given without veterinary guidance.
• Do not force food. Focus on hydration first.
• Do not use ice baths or ice water. For suspected heat stroke, use cool (not cold) water and get to emergency care right away.

If your dog’s temperature is 104°F (40°C) or higher, or they seem weak, confused, or are having trouble breathing, treat it as urgent and contact an emergency clinic.

Heat stroke: what to do now

If you suspect heat stroke, do not “wait and see.” Go to an emergency vet immediately. While you are getting out the door and during transport, these steps can help:

• Move to a cooler area right away (shade, air conditioning, fan).
• Apply cool water to the body, especially the belly, armpits, and paw pads. Avoid ice-cold water.
• Use airflow (fan or car AC) to support evaporative cooling.
• Do not force water if your dog is weak, vomiting, or not fully alert.
• Stop active cooling around 103°F (39.4°C) if you are monitoring temperature, then head straight in for veterinary care.

When to seek urgent care

Contact an emergency clinic or your veterinarian right away if you notice any of the following:

• Temperature 104°F (40°C) or higher
• Temperature 103°F (39.4°C) with significant lethargy, pain, or worsening symptoms
• Suspected heat stroke (recent exposure to heat, heavy panting, drooling, collapse)
• Repeated vomiting or diarrhea, or blood in stool or vomit
• Seizures , disorientation, severe weakness, or collapse
• Difficulty breathing or pale or blue-tinged gums
• Puppies, senior dogs, or dogs with chronic disease (they can deteriorate faster)

How vets find the cause

At the clinic, your veterinarian will typically start with a physical exam and temperature confirmation, then recommend testing based on symptoms and risk factors (like tick exposure, travel, kennel or daycare exposure, and vaccination status).

• Bloodwork (CBC and chemistry panel) to look for infection, inflammation, organ stress
• Urinalysis for urinary tract issues and hydration status
• Fecal testing if gastrointestinal symptoms are present
• Tick-borne disease tests depending on geography and exposure
• X-rays or ultrasound if there is concern for pneumonia, abdominal inflammation, or internal infection
• Culture tests for certain infections

How dog fever is treated

Treatment is targeted to the underlying cause, plus supportive care to help your dog recover comfortably.

Supportive care

• Fluids (oral encouragement at home or IV or subcutaneous fluids at the clinic)
• Rest and reduced activity
• Veterinary-prescribed medications to reduce fever and discomfort when appropriate

Cause-specific treatment

• Antibiotics for confirmed or strongly suspected bacterial infections
• Antiparasitic or tick-borne protocols when indicated
• Anti-nausea and GI support for vomiting and diarrhea
• Anti-inflammatory or immune-modulating therapy for immune-mediated conditions
• Emergency cooling and intensive monitoring for heat stroke

The key takeaway: treating the fever alone is rarely the full solution. Finding and addressing the cause is what protects your dog long-term.

Prevention tips

You cannot prevent every illness, but you can reduce risk with a few consistent habits.

• Stay current on vaccines and regular wellness exams.
• Use veterinarian-recommended tick and flea prevention, especially in warm months.
• Prioritize dental care with brushing and professional cleanings when needed.
• Practice heat safety: avoid midday heat, provide shade and water, never leave dogs in parked cars.
• Be mindful of exposure: boarding, grooming, daycare, and travel can increase contact with contagious respiratory illness.
• Act early when your dog seems unwell. Early care often means simpler treatment.

Quick FAQ

Can I tell if my dog has a fever by touch?

You might notice warmth in the ears or paws, but touch is not reliable. A thermometer gives the only dependable answer.

How long can a dog have a fever?

It depends on the cause. Some mild viral illnesses resolve in a day or two, while bacterial infections or immune conditions can persist and worsen without treatment. If fever lasts more than 24 hours or your dog is clearly sick, contact your veterinarian.

Should I feed my dog if they have a fever?

Hydration is the first priority. If your dog is willing, offer a small, bland meal, but do not force it. Your veterinarian can guide you if appetite loss continues.

A steady plan helps

I always remind pet parents that small, consistent observations make a big difference. If your dog seems unwell, check what you can safely check, write down symptoms and timing, and get guidance early. With prompt care, most dogs bounce back well once the underlying cause is addressed.

Designer Mixes note: This article is for general education and is not a substitute for veterinary diagnosis or treatment.