Pet Health
Fever in dogs is quite common, but it may also be a warning sign of serious health issues. Identifying the right cause allows you to act promptly and prevent unwanted consequences. In this article, Pet5H will walk you through 37 common causes of fever in dogs, grouped by disease categories, to help you better understand your pet’s condition and take the right action.
Signs Your Dog May Have a Fever
Before determining the cause, watch for the following common signs:
- Body temperature higher than 39.5°C (normal range: 38–39°C).
- Loss of appetite, refusal to nurse (in puppies), fatigue, trembling.
- Rapid breathing, dry nose, red eyes.
- Lethargy, unwillingness to move.
- May also be accompanied by vomiting, diarrhea, or seizures
- The most accurate way to measure temperature is with a rectal thermometer designed for pets; avoid estimating by touch.
I. Common Bacterial Infections
Dog Fever with Seizures Caused by Bacterial Infections
Dogs may develop a high fever ranging from 40.6 to 41.1°C, accompanied by profuse yellow discharge from the eyes and nose, persistent coughing, diarrhea, and mild tonsillitis. Red eyes, loss of appetite, vomiting, and swelling of the paw pads and nose are common symptoms.
In the later stages, dogs may experience seizures in the temporal muscles — a warning sign of a severe infection. However, symptoms such as paralysis or inflammation of the stomach, intestines, and lungs do not always occur.
Tonsillitis and Household Dog Diseases
Dogs with tonsillitis typically develop a mild to moderate fever, frequent coughing, and may vomit frothy fluid. The Lymph nodes in the head and neck become swollen, and in some cases abscesses may form, leading to pain and difficulty swallowing. Both tonsils are enlarged, reddened, and may partially obstruct the throat. This condition is commonly seen in household dogs, particularly when they are kept in poorly ventilated environments or after exposure to cold drafts or contaminated water.
Dog Fever Caused by Pneumonia
When dogs develop pneumonia, they typically present with a prolonged high fever, marked difficulty breathing, and persistent coughing. Yellow or green purulent discharge may be seen from the nose and eyes,often accompanied by vomiting and respiratory distress. Laboratory examination of the discharge can reveal characteristic pathogenic microorganisms. Pneumonia in dogs progresses rapidly if not treated promptly,and is particularly dangerous for puppies, elderly dogs, or individuals with weakened immune systems.
Dog Fever Caused by Bronchitis
Bronchitis in dogs is characterized by persistent coughing, fever, and difficulty breathing. It is most commonly observed in older or overweight dogs, particularly among herding breeds kept in dusty or high-humidity environments. In chronic cases, the inflammation can extend into the lower respiratory tract, compromising lung function and significantly reducing the dog’s quality of life if not properly managed.
Dog Fever Caused by Enteritis (Intestinal Inflammation)
Dogs with enteritis typically present with prolonged fever, persistent diarrhea, dehydration, and rapid weight loss. Affected dogs become weak, emaciated, and noticeably fatigued. Without timely fluid and electrolyte replacement along with appropriate treatment, the inflammation can spread leading to severe complications in the gastrointestinal tract, impairing nutrient absorption, and posing serious risks to the dog’s overall health.
Fever in Dogs Caused by Ear-Nose-Throat (ENT) Infections
Bacterial infections in a dog’s ears, nose, or throat can cause fever and localized pain. Depending on the severity of inflammation, clinical signs may include nasal discharge, foul odor from the ears, difficulty eating, frequent sneezing, or abnormal head tilting. If left untreated, the infection may extend to deeper structures of the upper or lower respiratory tract, resulting in more serious complication.
Fever in Dogs Due to Streptococcus Infection in the Reproductive System
Dogs with Streptococcus infections of the reproductive tract often present with elevated body temperature, foul-smelling vaginal discharge, and difficulty mating. In some cases, miscarriage or stillbirth may occur. The infection can be transmitted through mating or due to poor hygiene after whelping. Bacterial culture typically confirms a high concentration of Streptococcus in the affected tissues.
Dog Fever Caused by Sinusitis
Sinusitis in dogs often originates from dental infections, particularly involving the upper molars. Affected dogs may develop fever, with the sinus region becoming extremely sensitive to touch, and intermittent nasal discharge is commonly observed. Nasal discharge may occur intermittently. If left untreated, the infection can extend to adjacent structures such as the eyes or upper respiratory tract, potentially leading to serious complications.
Dog Fever Caused by Peritonitis
Dogs with peritonitis typically present with high fever, generalized weakness, and marked abdominal pain on palpation. The abdomen may appear distended, bloated with gas, or abnormally soft. Affected dogs often lose their appetite,have difficulty moving, and become lethargic. Without prompt treatment, peritonitis can progress to systemic infection, posing a serious life-threatening risk.
Dog Fever Caused by Septicemia (Blood Infection)
Dogs with septicemia typically present with high fever and rapidly progressing systemic weakness. The bloodstream infection can lead to severe damage and hemorrhage in multiple internal organs.Microbiological testing usually confirms the presence of pathogenic bacteria in the blood. This condition is a medical emergency requiring prompt intervention with broad-spectrum antibiotics and fluid therapy.
II. Group of highly dangerous infectious and special communicable diseases
Dog Fever Caused by Infectious Canine Hepatitis
Dogs affected by infectious canine hepatitis typically present with high fever, generalized weakness, conjunctivitis, oral inflammation, and enlargement of the tonsillar lymph nodes. In acute cases, sudden death may occur. Palpation of the liver often elicits a pronounced pain response clinical signs include vomiting, diarrhea, coughing, and corneal opacity, which is observed in approximately one-third of cases.
Marked jaundice is commonly seen, along with hepatomegaly featuring white foci, gallbladder edema, abdominal distension due to ascites, internal hemorrhage, and enteritis. In some cases, bloody diarrhea may also be present.
Leptospirosis in Dogs
Dogs infected with Leptospira may die suddenly as a result of severe complications. Typical clinical signs include fluctuating body temperature, sunken eyes, vomiting, and pronounced pain on palpation of the lumbar region. The breath often carries a strong fetid odor; the teeth may be coated reddish plaque, and the tongue and oral mucosa may present with severe ulceration. The disease can also cause jaundice, foul-smelling ocular and nasal discharge, and gingival bleeding. Internal organs such as the liver, kidneys, lungs, and small intestine frequently exhibit congestion and hemorrhage. Chronic renal injury may progress to kidney failure.
Fever in Dogs Caused by Tuberculosis
Tuberculosis in dogs is uncommon but can occur, particularly through exposure to infected livestock or contaminated environments. Affected dogs typically present with chronic coughing, ocular and nasal discharge, weakness, and reduced appetite. Postmortem examination may reveal small pinkish-white nodules in the liver, peritoneum, lungs, pericardium, and heart. Lymph nodes are often enlarged. In puppies, clinical signs may include vomiting, lethargy, and rapid death if untreated. Cytological or microbiological analysis of exudates frequently demonstrates the presence of Mycobacterium under microscopic examination.
Fever as a Symptom of Tetanus in Dogs
Dogs with tetanus typically present with ears held tightly against the head, sunken eyes, and a markedly prolapsed third eyelid. The body becomes rigid, with difficulty walking, stiffness of the neck and tail, and trismus (“lockjaw”) preventing the mouth from opening. As the disease progresses, fever often develops, accompanied by seizures and impaired motor function. The characteristic “sardonic grin” — an abnormal retraction of the lips — is considered a valuable clinical indicator, although it is not present in all cases
Fever in Dogs Caused by Anthrax
Anthrax in dogs usually develops after ingestion of meat contaminated with Bacillus anthracis usually develops after ingestion of meat contaminated with Bacillus anthracis. Given its zoonotic potential, anthrax is considered extremely hazardous. Immediate response requires strict quarantine measures, safe carcass disposal, and thorough environmental decontamination in accordance with veterinary public health protocols.
III. Parasitic Diseases
Toxoplasma Infection in Dogs
Symptoms of toxoplasmosis in dogs are diverse and often nonspecific. Clinical signs may include diarrhea, neurological abnormalities such as limb dragging, purulent nasal discharge, anorexia, coughing, pneumonia, peritonitis, and fever. In some cases, abdominal pain, abortion, or stillbirth may occur. On gross examination, tiny white pinpoint lesions may be observed in the liver, spleen, heart, and pancreas. Histopathological evaluation typically reveals the presence of Toxoplasma gondii, with a pathogenic mechanism resembling that of bacterial or viral infections.
Coccidiosis in Dogs
Coccidiosis is a common parasitic disease in puppies between 8 and 12 weeks of age, It is particularly prone to occur after puppies are brought home from pet shops or exposed to a new environment. Clinical signs typically include bloody diarrhea, rapid dehydration,emaciation, and mild to moderate fever. In severe cases, the disease can lead to sudden death. Neurological signs as well as purulent ocular or nasal discharge may also be observed. Diagnosis is confirmed by microscopic detection of coccidian oocysts in feces or rectal samples.
Babesia Infection in Dogs (Babesiosis)
Babesiosis is a tick-borne hemoparasitic disease transmitted by Rhipicephalus spp. ticks. Affected dogs typically present with high fever, lethargy, vomiting, polydipsia, and prolonged diarrhea. In some cases, bile may be observed in feces or vomitus, accompanied by constipation and marked icterus. Clinical signs can include blood-tinged saliva, dyspnea, mucocutaneous hemorrhages, generalized edema, and restlessness. Urinalysis often reveals hemoglobinuria, giving the urine a characteristic red discoloration. The disease is particularly severe in puppies but can also be fatal in adult dogs if not diagnosed and treated promptly.
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