Is a nosebleed a minor issue requiring basic first aid or an emergency requiring prompt veterinary treatment? H&H explains…
Although nosebleeds in horses can look alarming, they are reasonably common and in most cases are not serious. Even a small bleed – or epistaxis as vets describe it – can look dramatic, particularly when suffered by a grey horse.
A true nosebleed tends to happen at rest, while blood seen in the nostrils after hard work is more likely to be originating from the lungs.
There are some causes of nosebleeds that are a serious cause of concern as they risk leading to extensive loss of blood and even death if left untreated.
Nosebleeds in horse: Is it serious? | Causes | Treatment | Diagnosis | Prognosis
Is it serious?
Most minor nosebleeds are not serious, with only a small amount of blood lost and the bleeding typically stops within 15min. If a bleed continues for longer than this, then you should contact your vet even if the amount is just a trickle.
Consider how much blood the horse has lost. Would the drips slowly fill a mug or rapidly overflow a bucket? If a Thoroughbred-sized horse loses more than about four litres (say half a big bucket) of blood rapidly, then you should call your vet as an emergency.
Is the blood coming from one nostril or two? A true nosebleed originating from within the head will normally emerge from one nostril. A horse bleeding internally from the lungs then blood is normally seen from both nostrils.
Is there any obvious reason for the bleeding? Has the horse knocked its head, had a fall or the vet has just passed a stomach tube up the nose? In these cases the bleed should be monitored and appropriate action taken based on the amount of blood being lost and the period of time the bleeding continues.
Has the horse just been exercising hard? If so then it is more likely to have an exercise-induced pulmonary haemorrhage, when the blood originates from the lungs.
Is it a one-off nosebleed? This may be a minor bleed that hopefully will not recur. If it has happened repeatedly this could a sign of a more serious problem and should be promptly investigated by your vet.
Common causes of nosebleeds in horses
Horses do not tend to have spontaneous nosebleeds, so there has to be a reason why the bleed has occurred.
A nosebleed occurs when any part of the nasal passages (which are richly supplied with blood vessels), throat, lower airways or lungs are injured to such a degree that blood vessels are damaged and blood leaks out.
The commonest cause is a simple knock on the head, when as a result of the head trauma an alarmingly large amounts of blood may pour from one nostril. Such traumatic nosebleeds are usually self-limiting, but always consult your vet.
Nosebleeds can also occur if the delicate nasal tissues are knocked inadvertently, for example, when a vet passes a stomach tube up from the nostril. Sometimes this is inevitable, particularly if the horse moves at the wrong moment, but the bleeding always stops.
A moderate nosebleed, if accompanied by coughing, could suggest a foreign body wedged in the nose or throat.
More serious problems include a progressive ethmoid haematoma, which is a lump that can grow inside the horse’s nose. It is similar to a giant blood blister and is aptly described as a “bleeding polyp”. It is a rare condition seen in around one horse in 2,500.
Guttural pouch mycosis is the typical and most serious cause of repeated nosebleeds, unrelated to exercise or trauma, and is a very serious condition that requires surgery to control the bleeding. Horses suffering from this condition can die of blood loss, so it should never be under estimated.
Occasionally tumours somewhere in the respiratory tract or inflammation of the sinuses (sinusitis) will produce a trickle of blood from the nose.
Bleeding from both nostrils after exercise is most commonly due to an exercise-induced pulmonary haemorrhage. This happens when bleeding occurs from the blood vessels within the lung and is associated with strenuous exercise, for instance, racing or eventing at a high level. Because the blood is coming up from the lungs, technically it is not a true nosebleed at all.
Treatment of a minor equine nosebleed
With any nosebleed, the horse should be kept as calm as possible. Do not try to pack the nose to control the bleeding as this will prevent your horse from breathing. Horses cannot breath through their mouths.
It may help to hold an ice pack or cold wet towel just below the horse’s eyes. If the bleeding is coming from inside the nose area, this may reduce it.
The average thoroughbred-sized horse will carry around 50litres blood inside them, so what looks like a lot coming out of the nose may not be critical for the horse. However, nosebleeds should not continue for more than 15min; if one does, your vet should be consulted.
Diagnosing the cause of nosebleeds in horses
When investigating the cause of a recurrent or persistent nosebleed, vets may use a range of techniques including most commonly endoscopy, where flexible tubing with a camera at the tip, allows the vet to see inside the nasal passages and airways to try and pinpoint the cause of the bleeding. If the bleeding is coming from within one of the bony sinuses (hollow cavities within the skull), it may be necessary to drill into the sinus to insert the endiscope and examine the interior. Other forms of imaging including X-rays, MRI and CT scans may also be use by the veterinary team to identify the problem after which appropriate treatment can be given.
Prognosis of nosebleeds in horses
In cases where a horse has suffered a one-off minor nosebleed, the vast majority will make a quick recovery and suffer no on-going issues as a result. The prognosis is more guarded in horses that suffer repeat nosebleeds and a vet should always investigate these. The outlook will depend on the specific cause, with some conditions requiring surgery.
You may also be interested in…
‘A ticking time bomb’: what you need to know about deadly guttural pouch mycosis *H&H VIP*
Fungus that grows undetected in hidden cavities called the guttural pouches can have devastating consequences, as Andrea Oakes and Phil
How to treat ethmoid haematomas [H&H VIP]
With their origins hidden within the nasal cavities, ethmoid haematomas can obstruct the airways and cause nosebleeds. Gaining access to
Nosebleeds in horses after hard work [H&H VIP]
What is the significance of blood in a horse’s nostrils after hard work? Dr Colin Roberts discusses exercise-induced bleeding and
Haematomas in horses: how to beat them *H&H VIP*
A sudden and dramatic swelling could be a bleed into the body tissues, called a haematoma. Gil Riley MRCVS outlines
Horse health week: How to recognise, avoid and manage respiratory problems
Dr David Marlin explains why riders shouldn't think a horse that coughs during its warm-up is in the best of
