If you have a dog, chances are he's already become part of the family. So, what do you do when man's best friend develops a nosebleed? Also known as epistaxis, bleeding from the nose in a dog can be caused by a variety things, including infection.

Infection

Bacterial or fungal infections in a dog's nasal passage can result in a nosebleed. Other infections throughout the dog's body, like those in the blood and bone marrow, such as Rocky Mountain Spotted Fever or Erlichia, can also cause a dog's nose to bleed

Disease

Diseases like von Willebrand's disease and hemophilia can lead to bleeding of your dog's nose. Such diseases cause blood-clotting issues and keep the blood vessels from healing once they're irritated. Severe dental disease in a dog may also lead to an infection in the nasal cavity and have a similar result. Cancer or tumors in the nose erode the tender tissue and blood vessels and can also cause severe nose bleeds.

Trauma

A dog's nose bleed may be the result of an injury or trauma to the head or nose. Such accidents often cause the nose to bleed profusely.

Irritation

One of the most common causes of dog nose bleeds, irritation to the nasal passage by debris, like grass, pollen or burrs, often leads to sneezing, followed by blood from the nose. If a dog is constantly pawing at his nose, he may have something stuck in the nasal passage causing the bleeding.

Poison

If a dog ingests a poison, like rat poison, the poison's anticoagulant effect may cause the nose to bleed for days or even weeks.

Source:

Dogs with Nosebleeds

The Dog Health Guide: Canine Nose Bleeding and Tumors

Epistaxis in Dogs