Nosebleeds are a very common events with horses. The medical term for nosebleeds is epistaxis. Though frequently just a one time event, they can also be the harbinger of serious disease. Some of the causes are ethmoid hematoma, guttaral pouch mycosis, and exercise induced pulmonary hemorrhage. This article concerns itself with the differentiation of the various causes of nosebleeds and the treatment and prognosis of the various conditions. Links are provided to more detailed articles on the diseases.

That can be a difficult question to answer with certainty. The incidence of minor nose bleeds for no apparent cause is common in horses. We assume most of these one-time events represent unobserved trauma. Usually these events do not have a lot of bleeding: just the short duration of dripping blood that may recur for short periods several times over the next couple of days. Then it never returns. However each of the serious problems will start in this same way and in the case of guttural pouch mycosis may lead to a rapidly terminal event. So how do you evaluate a nose bleed the first time you see it?

First is to assess how much blood is being loss and how quickly. A full size horse can lose up to 1.5 gallons of blood. This translates to a drop a second (drip thousand, drip thousand, drip thousand, etc . . . ) for at least 12 hours as maybe as long as 24 hours before life threatening consequences occur. If the blood is pouring out of the nose first aid may be helpful and of course, you should seek professional help. For first aid: unless coughing or difficult breathing is occurring, elevate the head to above its normal position. If the bleeding is coming from the upper respiratory tract, this will significantly lower the pressure at the bleeding location to help slow and clot. It will also make it more difficult for the horse to clear the blood out of the way of his trachea, so be careful that this does not impair breathing or cause coughing.

Just because the bleeding is not rapid or intermittent does not mean that it is not serious. Early on, disease that may require extensive treatment might present with minor bleeding. However the bleeding will generally return and worsen over time. Recurrent bleeding from the nose that worsens over time deserves a closer investigation.

So we are back to the original question: when should a nose bleed be taken seriously and have an examination and work up? Well blood pouring from the nose needs immediate help and some first aid. For milder bleeding I guess it depends on your tolerance for risk. Those with a very low tolerance for risk probably will call the vet out the first time a little pink appears at the nose. Most will probably wait out a single incident of dripping that stops in less than 30 minutes. Though that first incident of dripping is very likely to be a minor event, you cannot be sure without an exam.