Fevers in Cats

How can you tell if your cat has a fever? In humans, a kiss of a warm forehead may give you a clue. But you can't tell if your cat has a fever by feeling for a warm, dry nose, as many people believe. The only way to know for sure – with either a human or a cat – is to take their temperature.

A normal temperature in cats is higher than it is in humans and ranges from 100.4 to 102.5 F. A fever in cats occurs when temperatures rise above 102.5 F. Although fevers may be helpful in fighting disease, a fever higher than 106 F can be dangerous. It can even damage organs. Contact the vet right away if your cat has a high fever. But keep in mind that high temperatures in cats tend to be less harmful than in dogs.

Learn about the causes, signs, and symptoms of fevers in cats and what you need to know about taking your cat's temperature and caring for a cat with a fever.

Causes of a Fever in Cats

An increase in body temperature above normal is called hyperthermia. Abnormal or unregulated hyperthermia in cats may result from being in a very warm environment or having increased muscle activity, for example. But these are not examples of a fever. A fever is a specific, regulated type of hyperthermia. It develops when the set point is increased in the hypothalamus, a part of the brain that acts as the body's thermostat. A fever usually results when the immune system is activated by conditions such as:

  • A bacterial, viral, or fungal infection
  • A tumor
  • Injury from trauma
  • Certain medications
  • Diseases such as pancreatitis or lupus

A fever for more than two weeks with no apparent reason is called a fever of unknown origin (FUO).

Signs of a Fever in Cats

Diseases that cause a fever in cats can also cause certain telltale behaviors. These behaviors, which evolved in wild animals to help them survive illness, allow cats to conserve the necessary energy to produce a fever. Fevers fight disease by stimulating the immune system and slowing growth of bacteria and viruses.

Watch for these signs of a fever:

  • Loss of appetite
  • Depression
  • Lack of energy or activity
  • Decreased drinking
  • Decreased grooming
  • Shivering or rapid breathing

Your cat may also display other specific signs of illness, such as sneezing or diarrhea.