Seasonal Conjunctivitis in Horses: Causes, Symptoms and Treatments

Seasonal conjunctivitis, commonly known as hay fever or pink eye in horses, is an inflammatory eye condition that significantly impacts equine health. This condition typically arises during specific times of the year, causing discomfort and potential vision impairment in affected horses. 

What is Seasonal Conjunctivitis?

Seasonal conjunctivitis is a condition that afflicts horses by provoking inflammation in the conjunctival membrane of their eyes. The conjunctiva is a delicate, transparent tissue that lines the eyelid's inner surface and covers the white part of the eye. This inflammation can result in various symptoms, such as eye redness, tearing, and discomfort, ultimately affecting the horse's ocular well-being.


Allergens: The primary instigator of seasonal conjunctivitis in horses is environmental allergens. These allergens include pollen, dust, mould and even insect bites and can incite an inflammatory response when they come into contact with the eye, 

Environmental Factors: Seasonal conjunctivitis often manifests during specific seasons when allergen concentrations are higher. Notably, it is prevalent during spring and late summer. Spring ushers in a surge of allergens, particularly pollen from various grasses, trees and flowers, making it a prime time for this condition to develop. As summer transitions into autumn, the prevalence of ragweed pollen rises, becoming a substantial trigger for allergic reactions in horses.


The symptoms of seasonal conjunctivitis in horses encompass a range of discomforting ocular signs:

  • Watery Eyes: Excessive tearing, often accompanied by a noticeable increase in ocular discharge.
  • Swelling: The eyelids may become swollen and exhibit redness.
  • Squinting: Horses may squint or partially close their eyes due to the discomfort caused by the inflammation.
  • Discharge: Ocular discharge can vary in consistency from clear to pus-like.
  • Photophobia: An increased sensitivity to light, causing horses to shy away from bright environments.


Effective treatment for seasonal conjunctivitis hinges on the severity of the condition. Treatment options include:

Allergen Management: Stable your horses during peak allergen periods to minimise exposure to allergens. If needed, use fly masks to protect the eyes.

Topical Medications: Veterinarians may prescribe eye drops or ointments to reduce inflammation and control potential infection.

Oral Medications: In more severe cases, veterinarians may recommend oral anti-inflammatory or antihistamine medications.

Environmental Control: Regularly clean the horse's living quarters to reduce allergen exposure.

Professional Veterinary Care: Consult your veterinarian for an accurate diagnosis and a tailored treatment plan.

Herbal Remedies: You can make a soothing eye wash with chamomile tea. This remedy's anti-inflammatory properties can help alleviate eye irritation. You can also use calendula as an herbal eye drop to aid in reducing inflammation and managing potential infections.

And aloe vera gel can have a soothing and anti-inflammatory effect. However, always consult your veterinarian before using herbal remedies to ensure their safety and appropriateness for your horse's condition.

Seasonal conjunctivitis in horses, driven by environmental allergens, leads to eye inflammation and distress. By integrating conventional and herbal remedies, you can ensure your horse's optimal health and comfort, ultimately enhancing their overall well-being. However, please consult your veterinarian for a precise diagnosis and treatment plan tailored to your horse. 

For other herbal allergy symptoms see the Sneeze Free formula