Graphic courtesy MarVistaVet

Some blood-tinged droplets sneezed on the floor might be the only sign, or there might be a steady, inexorable bloody drip from one or both nostrils. These findings are alarming as well as messy in the home and we want to identify the cause and take care of it promptly if it is possible to do so. The problem is that there are many causes, and not all of them are localized to the nose, and many are very serious diseases. The following is a review of tests typically necessary to get to the bottom of the bloody nose as well as the conditions that might be responsible.

First Aid

So, you are at home with your pet and a bloody nose starts and does not seem to be stopping. Here are some tips to get the bleeding controlled in the time prior to your vet appointment:

• Keep yourself calm. If your pet sees you getting frantic, they will, too. Excitement = higher blood pressure = more bleeding.
• Get an ice pack and apply it to the bridge of the nose (obviously, be sure your pet can breathe around the ice pack). The cold will constrict small blood vessels, which will slow the bleeding.
• Do not insert absorbent material or cotton swabs in the pet's nose, as this will generate sneezing, which will make the bleeding worse. A dose of an oxymetazoline nasal spray such as Afrin may help constrict blood vessels and lead to relief.
• If the pet has a condition that involves recurring nose bleeds, consider the oral use of the Chinese herb Yunnan Baiyo, which promotes blood clotting tendency. Ask your veterinarian for details.

Information Your Veterinarian Will Need

You can help your veterinarian tremendously by taking some time to think about the following information and bringing up anything pertinent.

• Does your pet take medication? Non-steroidal anti-inflammatory medications (aspirin in particular) will inactivate blood clotting factors. Do not assume your vet knows all the medications your pet is taking; list them for your vet.
  
  
• Do you have any rat poison or has your pet been consuming any dead rodents that might have been poisoned? Most rat poisons act by disabling the ability to clot blood.
  
  
• Look closely at your pet's face. Is there any deformity or asymmetry? Is the bridge of the nose swollen? Are either of the third eyelids elevated? Does one eye seem to protrude more. does one eye tear more? Does the nose leather (textured tip) look normal?
  
  
• Could there have been any trauma to the nose? Does your pet play roughly with another animal?
  
  
• Is your pet exposed to foxtails or other grass awns that could become lodged in the nose?
  
  
• Has your pet been sneezing? Has the pet been rubbing at the nose?
  
  
• Open your pet's mouth if possible. Look at the gums under the lips. Is there blood in the mouth? Do the gums seem pale? If they are, this suggests a serious loss of blood and you may have an emergency on your hands.
  
  
• Is there any evidence of bleeding anywhere besides the nose? You may see a black tarry stool with Intestinal bleeding may present with a black tarry stool. Any unusual bruising should be reported. Any unexplained swelling that might be bleeding under the skin should also be noted.
  
  
• Is this the first nosebleed or have there been others?
  
  
• Is the blood coming from both nostrils or only one?

Where to Start

After the veterinarian performs a general examination of your pet, some more specific tests are needed with the idea of prioritizing the most likely conditions and least invasive forms of testing.

Blood Tests First

A basic blood panel and urinalysis will probably be needed as a database for the animal’s health as well as to assess the degree of blood loss. This information also serves as a pre-anesthetic evaluation should rhinoscopy or nasal imaging become necessary. A platelet (a blood cell involved in blood clotting) count will be needed as will coagulation tests (common tests are the PT or prothrombin time; the PTT or partial thromboplastin time; the ACT or activated clotting time; and the buccal bleeding or symplate time.) These tests evaluate a complicated biochemical cascade responsible for clotting blood. The pattern of abnormalities found in these tests will sort out blood clotting disorders.

Other blood tests that may be helpful involve titers for fungal infections, a classic cause of the nosebleed. Fungi are inhaled and if the patient is immune-compromised or excessively exposed, the fungus can take root and begin to grow in the nasal cavity.

In cats, the most common nasal fungal infection is caused by Cryptococcus neoformans. The good news here is that a blood test for fungal antigen is very accurate. Any positive number is significant and warrants treatment.

In dogs, fungal infections are not so simple. The most common organisms are Aspergillus fumigatus and Penicillium species. Blood tests are not as accurate especially since there are other species of Aspergillus besides fumigatus and each requires its own blood test. Complicating matters is the fact that nasal tumors predispose a dog to fungal infections so a dog can easily have both problems in the same nose. Blood tests for fungal infections may be included in the initial battery of tests. A negative Aspergillus test does not rule out Aspergillus infection.

Blastomyces dermatitidis is another fungus that can get into a dog's nose. Urine antigen testing is accurate for diagnosis and blood testing is also available if results are ambiguous. As with other fungi, treatment is long term and challenging.

Another condition worth mentioning is hyperviscosity syndrome. In this situation, an extremely high blood protein level makes the blood so thick that blood vessels break from the pressure. Certain types of cancer (multiple myeloma, lymphoma, and certain types of leukemia) as well as infection with Ehrlichia canis, a blood parasite can cause this syndrome.

A routine blood panel should show the unusual globulin levels that typify hyperviscosity syndrome.

Another relatively simple parameter to measure is blood pressure. High blood pressure can occur as a complication of numerous diseases. When blood pressure rises, small blood vessels begin to burst and bleed, not just in the nose but often in the eyes or nervous system as well. Do not be surprised if your veterinarian checks for retinal hemorrhage.

Tick-borne infections (Ehrlichia, Babesia, and others) commonly involve low platelet counts. Platelets are blood cells involved in clotting and when they become infected with blood parasites, they do not work properly in the clotting cascade. Tick panels are blood panels that screen for infection with numerous tick-borne parasites, most of which can be managed or eradicated with antibiotics.

The bottom line is that there are many causes of nose bleeds but many can be ruled out with non-invasive testing and it is the non-invasive tests that we want to perform first.

Blood Clotting Disorders of Pets

• Rat poisoning
• Von Willebrand's disease
• Hemophilia
• Liver failure
• Disseminated intravascular coagulation

Diseases Causing a Low Platelet Count

• Immune-mediated thrombocytopenia
• Anaplasma infection
• Bone marrow disease
• Drug reactions (methimazole, chemotherapy drugs, excess estrogens, sulfa class antibiotics) 
• Feline leukemia virus infection
• Feline immunodeficiency virus (FIV)
• Ehrlichia infection (dogs) 
• Rocky Mountain spotted fever
• Hemangiosarcoma
• Other cancers
• Babesia

Cruising Towards Anesthesia

If the basic blood tests and clotting parameters are normal, then the chances are that the problem is localized to the nose but there are a few more tests that are required before the patient is anesthetized for a nasal examination.

• Radiographs of the chest should be performed to rule out obvious cancer spread or obvious disseminated fungal disease.
• An oral examination should be performed as best as possible. Dental disease can be bad enough to create nasal bleeding, given that the roots of larger teeth connect with the nasal cavity. Oral tumors that have eroded into the nasal cavity may be evident if one can get a good look in the mouth. Many patients will not allow much oral exam and certainly probing the gums and getting a thorough inspection will require anesthesia but it is absolutely worth looking for obvious lesions if it is possible to do so.

Diagnostics Requiring General Anesthesia

Radiograph from a dog with a nasal tumor. The left side of the nasal cavity appears darker because the tumor has destroyed much of the fine bone quality. The right side of the nasal cavity still has its delicate bone structure which appears as an almost lacy texture. Photo courtesy MarVistaVet

If nothing has been revealed by the preceding tests, it is now time for radiographs of the nose, superficial rhinoscopy, and a dental inspection all of which require general anesthesia. Radiographs generally start the procedure as the other procedures might alter the radiographic appearance of tissues. The radiographs help evaluate the tooth roots and sinuses. Nasal tumors are common causes of nosebleeds in elderly dogs and the bone destruction they cause is evident on radiographs. Referral for more advanced imaging such as CT scanning or MRI, may be needed to determine the extent of bone destruction or to clarify radiography findings.

An otoscope (the same gadget used to look in your pet’s ears) can be used to look inside the nasal cavity superficially to remove foreign bodies lodged there. Deeper peeking requires an actual endoscope which may not be readily available in general practice.

The teeth can be cleaned under anesthesia with specific attention to the tooth roots (remember, an abscessed upper tooth root penetrates into the nasal sinus above.

If it seems appropriate to do so, some nasal discharge can be flushed through the nose and into a gauze sponge packing the throat. This may be helpful in identifying infectious organisms but may initiate more bleeding so some judgment is required on whether the benefit is worth the risk.

Then What?

If the simple tools of general practice do not reveal adequate information, referral for endoscopy may be needed. Deeper visualization of the nasal tissues is possible with this equipment, plus biopsy specimens can be taken although bleeding is the chief risk. Taking a biopsy is particularly difficult in the nose, not just because of the hemorrhage but because nasal tumors are surrounded by so much inflammation it is difficult to get a representative sample. Often it is not possible to see the area being biopsied directly, especially if prior sampling has led to bleeding.

If radiographs are diagnostic for cancer and aggressive therapy is contemplated, prognosis is highly dependent on the type of tumor so biopsy becomes especially important in this situation.

And Then What?

At the end of all these procedures, sometimes the area of bleeding is simply not accessible without surgery. This would be the final and most invasive procedure in retrieving a difficult foreign body or tissue sample. Extensive bleeding is expected and this is generally the last resort after a long road of diagnostics.

In a study by Bissett et al published in the December 15, 2007, issue of the Journal of the American Veterinary Medical Association, 176 cases of dogs with bloody noses were reviewed to determine which underlying causes were most common. Of these 176 dogs, a definite underlying cause was found in 115 cases.

• 30% had nasal tumors
• 29% had trauma
• 17% had nasal inflammation of unknown cause (idiopathic rhinitis)
• 10% had low platelets
• 3% had some other blood clotting abnormality
• 2% had high blood pressure
• 2% had tooth abscess

Conspicuously absent is the nasal fungal infection but since these are frequently regional in nature in dogs, the population studied may not have been in an area where fungi are common pathogens.

Other Relevant Studies

Evaluation of factors associated with survival in dogs with untreated nasal carcinoma: 139 cases (1993-2003) by Rassnick et al published in the Journal of the American Veterinary Medical Association  229:401-406, 2006.

This study reviewed the outcomes of 139 dogs diagnosed with nasal carcinoma. Since many dogs are euthanized at the time of this diagnosis, this study included only dogs that were alive seven days after the initial diagnosis was made. Dogs studied received only pain medication, anti-inflammatories and antibiotics (no surgery, chemotherapy or radiation therapy). The following statistical findings came out:

• 80% of dogs were purebred. The median age was 11 years and the median body weight was 48 lbs.
• 77% had nose bleeds. Median survival time for dogs with nosebleeds was 88 days vs. 224 days for dogs with carcinomas that did not have nose bleeds.
• Approximately half of the patients studied were felt to have improvement with the supportive care described above.

Ultimately, the therapy for a recurring nosebleed depends on the cause, and the causes are many and varied. If your pet has a nose bleed that lasts more than 5 minutes, seek veterinary care right away. If nose bleeds are recurrent, your pet will need a medical checkup to sort out the possible causes, as reviewed above. Contact your veterinarian to assess your pet's situation as early in the course of disease as possible.