Nosebleeds do not occur spontaneously in cats. However, the nasal cavity is extremely sensitive
and bleeds easily when traumatized. Most nosebleeds are associated with a blow
to the face that damages the nose. Others are due to an erosion of the nasal
membrane caused by a foreign body, infection, tumor, or parasite. Rarely, a nosebleed may be a
manifestation of a generalized clotting disorder such as that produced by a low
platelet count, liver disease, or exposure to rodenticide anticoagulants.
When a cat’s nose bleeds as a result of trauma, a midline fracture to the
roof of the mouth may also have been incurred. Suspect this if the cat exhibits
open-mouth breathing. This fracture can cause misalignment of the teeth, in
which case the alignment must be adjusted and the teeth wired together to
stabilize the upper jaw until it is healed. Any cat who has a nosebleed after
trauma to the nose should be seen by a veterinarian.
Cats can get a variety of intestinal parasites, including some that are commonly referred to as “worms.” Infestations of intestinal worms can cause a variety of symptoms. Sometimes cats demonstrate few to no outward signs of infection, and the infestation can go undetected despite being a potentially serious health problem. Some feline parasitic worms are hazards for humane health as well.
Treatment: Nosebleeds may be accompanied by sneezing spasms that aggravate the bleeding. Keep the
cat quiet and confined. Apply ice cubes or cold packs to the bridge of the nose
to reduce blood flow and aid clotting. Slight bleeding usually subsides
quickly, especially if the cat is kept quiet. Persistent bleeding is a cause
for concern. Call your veterinarian.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"