Seasonal Allergic Rhinitis in horses: What to look for and how to manage it

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Seasonal Allergic Rhinitis in horses: What to look for and how to manage it

As the sun begins to shine, bees become busier, and flowers begin to blossom, one thing is becoming certain - Spring is upon us. Whilst most of us will welcome this change in season, embracing the longer days that can be spent outside with our horses, many of us will also be reaching for antihistamines as those pesky pollen allergies begin to flare up.

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Causes of Seasonal Allergic Rhinitis in Horses

Unfortunately, these allergies don’t just stop with humans. Pollen irritation is also common in horses, and reactions are often more frequently reported in Spring, as this is the time when many plants and trees begin to bloom (although it is worth noting that similar reactions can also be caused by dust mites or mould spores year-round). To help spot and treat allergies and irritation, here is some guidance from one of our vets.

Symptoms of Seasonal Allergic Rhinitis

Horses’ noses act like an air filter, containing a layer of sticky mucus and tiny hairs to help prevent dirt and dust from entering the lungs. The large airways in the lungs also have a protective lining of mucus and microscopic hair-like projections, called cilia, which trap and remove microbes and debris, by continuously sweeping irritants up and out of the lungs.

If your horse’s respiratory system is sensitive to pollen, it’s likely the delicate lining of the airways will become irritated. The resulting inflammation may present as symptoms, including:

  • Coughing
  • Head shaking
  • Lethargy
  • Lost concentration
  • Poor performance
  • Behavioural problems
  • Nasal and eye discharge

What can you do to help your horse?

If your horse exhibits these symptoms, it may be suffering from pollen allergies, also known as Seasonal Allergic Rhinitis. To establish what exactly is causing discomfort in your horse, it is best to consult your vet sooner rather than later. It’s important to pursue treatment because, if left untreated, the lung inflammation associated with uncontrolled allergies can make your horse more susceptible to respiratory infections.

Typically, the first step in management involves avoiding pollen as much as possible. This can mean putting specific measures in place during the parts of the year when these allergies are likely to occur, often between April and September. As a general rule, I’d advise the following:

  • Avoid allowing your horse outside during the early hours of the day. Typically, pollen counts are at their highest between 5:00am and 10:00am, so if you’re used to exercising your horse first thing, a switch in routine may be necessary.
  • When outside, protect your horse with physical barriers such as pollen nets or face masks. These can be worn when out on a hack, and when grazing the field.
  • Where possible, avoid locations where you know there are particularly troublesome pollens, like Oilseed Rape, tree lined paths, and keeping grass shorter.
  • Respiratory supplements are also available, which may help as part of your management approach.

Treatment of Seasonal Allergic Rhinitis

A physical examination, together with possible diagnostic tests, will be required, to rule out other potential causes. This is because the symptoms of Seasonal Allergic Rhinitis are similar to other ailments, such as viral respiratory infections. If your horse is diagnosed with pollen allergies, then the steps above will help you to reduce the signs and ease your horse’s discomfort.

Prescription medication typically involves corticosteroids or 'steroids', and bronchodilators. These are given by to control and reduce the clinical signs. Corticosteroids may be required to control inflammation, either in an episode of acute respiratory distress or, at a maintenance level, to reduce chronic inflammation. Bronchodilators are used to relax the muscles in the airways and keep them open. These medications can be especially important during high-risk periods of the year, to improve their health and wellbeing. By speaking with your vet, you will be able to create a treatment plan to help your horse.

When is it time to see your vet?

  • Acute respiratory distress: flared nostril at rest, cough (single or persistent)
  • Chronic respiratory signs: cough at rest or associated with exercise, heave line, flared nostrils at rest, exercise intolerance
  • If you have taken the above measures but notice that your horse’s health still isn’t improving, it’s important to speak with your vet about prescription medication.

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Published: 13/03/2020
Last updated: 23/03/2021

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