Anemia in cats occurs when there aren't enough healthy red blood cells to carry oxygen to their body's tissues, making the cat tired and weak. There are two main causes of anemia in cats: Either they don't make enough red blood cells or something is destroying red blood cells faster than they can replace them.
Anemia can be a temporary, one-time problem, or it can be a long-term condition. Further, anemia can range from mild with no noticeable clinical signs to severe enough to be life-threatening. Because of this, cat anemia treatment varies depending on the severity and cause. Let's take a closer look as to what causes a cat to be anemic.
What Causes Anemia in Cats?
While red blood cells play a large role in diagnosing anemic cats, other causes may include the following:

- Internal or external parasites: A very common cause of anemia in kittens and feral cats, parasites like fleas or roundworms can suck enough blood out of a cat to cause anemia.
- Infectious diseases: Blood-borne parasites, including Mycoplasma and Cytauxzoon felis, can cause hemolytic anemia (destruction of red blood cells). Anemia is also associated with feline leukemia and feline immunodeficiency virus.
- Exposure to toxins: Cat-toxic foods, like garlic and onions, can cause anemia. Believe it or not, zinc from pennies minted after 1982, copper toxicosis, moth balls, skunk musk and ibuprofen can all cause hemolytic anemia.
- Autoimmune disease: Autoimmune anemia occurs when the cat's own immune system attacks and destroys red blood cells. Infectious causes, like the ones already mentioned, trigger autoimmune anemia. In addition, chronic bacterial infections, cancer, some medications, vaccine reactions and hormonal changes are also suspected to cause autoimmune anemia in some cats.
- Trauma: Hemorrhage from trauma, such as being hit by a car or bit by a dog, can cause life-threatening anemia if not treated immediately.
- Anemia of chronic disease: Conditions like liver disease, kidney disease, hormonal conditions or cancer can create chronic conditions in the body that reduce the body's ability to create new blood cells, causing non-regenerative anemia.
- Bone Marrow Damage: A wide variety of toxins, infectious diseases and cancers can result in damage to or the complete destruction of the bone marrow, which produces red blood cells. While sometimes this damage can be corrected if caught early, many times the damage is irreversible and healthy bone marrow is replaced by scar tissue.
- Inherited disorders: Feline congenital porphyria, a problem stemming from an enzyme deficiency, leads to hemolytic anemia and is a problem mostly seen in the Siamese cat breed.
- Nutritional deficiency: Anemia can occur in cats that do not get enough iron or cobalamin (vitamin B12).
What Are the Clinical Signs?
Anemic cats may show some of the following clinical signs:
- Exhaustion
- Lack of energy
- Loss of appetite
- Pale or yellow gums and skin
- Sensitivity to coldness
If a cat has a primary disease that is causing anemia, such as liver disease, kidney disease or cancer, then they may also show signs associated with those diseases.
