Key takeaways
Fever (also called pyrexia) is defined as an elevation of the temperature set point in by the body’s internal regulatory system (the hypothalamus).
- This is distinct from increased body temperature as occurs with heat stroke or exhaustion, where the set point remains normal (hyperthermia)
- The normal temperature of a dog ranges from 100.2-102.8°F (37.8-39.3°C). A fever over 105°F (>41°C) is a medical emergency
- Fevers are a natural immune response to infection
- Some fevers are self-limiting
- Diagnostics and treatment focus on addressing the cause of fever and the side effects, rather than the fever itself
- Fever also results from inflammatory processes
- Transient fever is a normal response to vaccination or surgery, for example
Connect with a vet to get more information about your pet’s health.
A closer look: Fever in Dogs
Fever is one of the immune system’s main responses to fight infections within the body and is not necessarily cause for concern. Consultation with a veterinarian is recommended for a temperature >103°F (>39.5°C) lasting for more than 24 hours. A moderate fever of 103 °F (39.4 °C) - 104.5 °F (40 °C) indicates a more urgent need for veterinary attention.
Temperatures >105°F (>41°C) require immediate medical attention as such temperatures can cause severe organ damage and conditions such as disseminated intravascular coagulation (DIC), which are life-threatening.
As fever is an immune response, it occurs as a response to another problem within the pet. Due to the wide range of causes, it is difficult to determine the appropriate level of concern for a febrile dog until the underlying cause is identified.
Risk factors
Fevers vary widely in severity. Fevers are most often caused by infections and inflammation.
Mild fevers associated with vaccination, surgery, or minor infections often go away without treatment.
Fevers usually come on suddenly, but may also show a cyclical, recurring pattern.
Most cases are accompanied by other symptoms which helps narrow down the potential cause.
Possible causes
Primary causes of fever often fall into one of the following categories:
Testing and diagnosis
Fever is easily identifiable by taking the animal’s temperature. Once it is identified, further diagnostics are required to determine the underlying cause of the fever. Such tests include:
- Physical examination
- Bloodwork
- Urinalysis
- Diagnostic imaging (x-rays, ultrasound)
- Specialized tests to identify infectious organisms such as viruses, fungi, or bacteria
Treatment of fever involves treatment of the underlying cause. With effective treatment, the fever is expected to subside alongside the underlying condition. As fever has a wide range of potential causes, treatment varies greatly depending on the underlying condition.
For cases involving extreme and sustained fever or severe secondary impairments, such as seizures or heart failure, fever-reducing medications (antipyretics) can be implemented to stabilize the animal while further treatment of the underlying condition is occurring.
Similar symptoms
Hyperthermia is a condition where the thermoregulatory set point remains at the correct level, but the body’s temperature is elevated due to an inability to cool off.
Associated symptoms
Symptoms of the underlying cause for the fever can vary widely.
