Nasal Discharge in Horses

Healthy Horse nose in article Nasal Discharge

Healthy Horses Nose

It’s that time of year again: summer is long gone, winter is upon us, and we are in a constant state of runny or blocked up noses. We won’t go anywhere without a travel pack of Kleenex in our handbag, and the usually quiet office is filled with a thousand and one ‘bless you’s. But it’s not just us humans that suffer from snotty noses; horses do too. But unlike us, who generally suffer from the change of the season, horses can suffer from nasal discharge all year round and for a number of reasons.

The majority of cases of nasal discharge in horses are not serious, and often caused by a mild respiratory infection that is easily treated. But if you observe serious or unusual symptoms of nasal discharge in your horse, be sure to contact your vet as soon as possible.

Causes of Nasal Discharge

Inflammation or bleeding in the respiratory tract, caused by illness or injury, causes nasal discharge in horses and other equestrian animals, due to an increase in mucus production in the nasal cavity and airways.

The most common causes of respiratory tract inflammation are viral, bacterial and allergic respiratory disease, although there are many other less common causes which can also result in nasal discharge.

Nasal discharge in horses can be separated into two groups: unilateral discharge and bilateral discharge.

– Unilateral Discharge –

Discharge that comes from just one nostril generally indicates that the cause of the problem is in front of the throat (pharynx), where both sides of the nasal passages communicate. The most common cause of this type of discharge is sinusitis. Cysts, tumours, hemorrhagic polyps and fungal infection in the sinuses, as well as dental disease/tooth root infection, guttural pouch infection, strangles and trauma is also causes of unilateral discharge.

– Bilateral Discharge –

Discharge that comes from both nostrils can be caused by any part of the respiratory tract. Common causes of bilateral nasal discharge in horses are viral or bacterial respiratory infection, allergic respiratory disease, EIPH (exercise-induced pulmonary haemorrhage), pharyngitis, pneumonia, guttural pouch infection and strangles.Nasal Discharge on a horse


A horse’s age, breed and use can give clues to the cause of their nasal discharge. The appearance of the discharge itself can also help to identify the cause. Here are some common causes, listed by discharge appearance:

  • Clear, mucus-like discharge: viral infection or allergic respiratory disease
  • Yellow or green discharge: bacterial infection
  • Smelly, unilateral discharge: tooth rot infection
  • Bloody discharge: EIPH, trauma, tumour at the back of the nasal cavity
  • Discharge containing food: swallowing disorder


The line of treatment recommended for your horse by your vet will depend upon the cause of the nasal infection. Viral conditions often require rest and anti-inflammatories. Bacterial infections can require antibiotics. Some sinus conditions will require surgery.


To both assist the treatment, and to prevent nasal discharge in the first place, ensure you do the following in your stable:

  • Feed on floor to assist natural drainage of respiratory tract and sinuses
  • Regular turn out
  • Isolation of unwell/infected horses

PLEASE NOTE: This article is meant for information only, and has not been written by a qualified vet –

If you are concerned about the health of your horse contact your vet as soon as possible.

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