Equine asthma

Equine asthma is an incurable and progressive condition. If left untreated, it can lead to scarring within the horse’s lungs.

But it’s not all bad – while asthma can’t be cured, it can be managed successfully with the right treatments and lifestyle adjustments.

What exactly is equine asthma?

In its early stages, equine asthma is a reversible narrowing of the airways. It’s usually caused by allergies, most commonly to dust or pollen.

The allergic reaction causes the production of fluid within the small airways, as well as thickening of the walls. As a result, the horse must breathe harder and faster. They often develop a cough as they try to clear the mucus.

Signs to watch out for

  • Coughing
  • Nasal discharge
  • Quick or heavy breathing
  • Difficulty exercising
  • A ‘heave line’ appearing (a line of visible abdominal muscles, caused by coughing)
  • Respiratory distress (they could suffer an acute attack if they’re repeatedly exposed to the allergen)

Mild to moderate equine asthma is difficult to recognize, so you need to look for these subtle signals, take them very seriously, and contact us as soon as possible, 

How will the vet diagnose asthma?

A presumptive diagnosis of equine asthma is usually made based on the history, clinical signs, and findings of an examination.

A more definitive diagnosis can be achieved by performing endoscopy of the airways – this allows us to visualise the upper respiratory tract and obtain samples by bronchoalveolar lavage (BAL).  The BAL samples can then be submitted for testing to diagnose the exact disease process that is causing the clinical signs.

Once we have the results, we will decide on a suitable treatment for your horse.


Treatment will depend on the severity of the horse’s symptoms.

If a case is caught early enough, keeping the horse on a ‘dust-free’ management system may suffice. This includes:

  • Avoiding the allergen that’s causing the reaction
  • Changing bedding to shavings or paper
  • Soaking or steaming hay
  • Dampening hard feed
  • Keeping stables well-ventilated

In more severe cases, your horse may need medical treatment. This can include an intravenous steroid injection, steroid powders and dilation of the airways using bronchodilators

When it comes to controlling your horse’s asthma, however, taking care of their living environment is very important. When equine asthma is not well managed, it can be a threat to your horse’s quality of life. By taking the right steps and closely working with our equine vets, you can effectively manage the disease so that your horse can feel better, be more active, and breathe more easily.  

If you think your horse may be developing asthma please call and speak to one of our equine vets.