Equine Summer Allergies


Summer! The season invokes a whole host of emotions for equestrians. We are excited to spend our days outdoors alongside our four-legged buddies, but along with the warmer days comes the frustrations that the heat and humidity can bring. A mid-south summer ushers in the potential for seasonal allergies from pests and pasture.

Respiratory and skin complaints are the most common ailments that can plague our horses. 

Respiratory: Heaves
Recurrent Airway Obstruction (RAO), more commonly known as heaves, is a respiratory disease that is caused by the horse’s environment. Heaves presents with a dry cough, labored breathing, and mucus drainage and can range from mild to severe. Horses with this disease can also develop what is known as a “heave line,” which is a visible line of tension in the abdominal muscles just below the ribcage. The horse’s nostrils may flare as its breathing becomes more labored. Heaves is most often a seasonal ailment that is triggered by environmental allergies, but can be observed year round in horses that are frequently exposed to dust or mold. The allergic reaction causes inflammation and restriction in the horse’s bronchial tubes, which then causes the labored breathing, coughing, and mucus buildup.  

A vet can diagnose heaves with a simple examination and offer a customized treatment plan. If you suspect your horse may have heaves, please work with your local vet to diagnose and treat them. Pasture allergies are somewhat common in the mid-south region, so an assessment of your horse’s pasture and identifying the plants they have access to can be very helpful. Check their hay, feed, and stalling environment for dust and mold. 

Skin: Sweet itch and hives
With summer comes bugs and lots of them! Irritation from biting and burrowing insects can cause a myriad of skin issues. One of these is Seasonal Equine Dermatitis, which most commonly presents with hives, smaller raised welts that appear suddenly on the skin, and  Sweet Itch, a condition characterized by incessant itching. Both Sweet Itch and hives are triggered by biting insects called “Culicoides” (mostly midges and gnats), whose saliva contains an irritant that can cause a hypersensitive reaction in some horses. Sweet Itch is accompanied by chronic itchiness, commonly seen on the belly, mane, tail, ears, and face. Constant scratching of the affected area can further compound the problem by causing sores and callouses. 

Hives are a sudden reaction that causes raised bumps on the skin that can appear anywhere on the horse’s body. It is important to rule out other allergies when hives are noticed, as they can be triggered by many allergens, including food. 

Prevention is the best measure for addressing these skin ailments. Dress sensitive horses in appropriate protective gear such as fly sheets, masks, and boots. Provide an escape from the bugs with proper shelter. Fans and insect screens can deter some pests, as well as the use of topical sprays. Keep manure picked up and eliminate any stagnant water sources, which can act as breeding grounds for some insects.  If you notice these skin conditions in your horses and are not able to manage them with prevention practices, a call to your vet can provide more custom treatment and prevention options.

Summer can be an enriching and fun time for equestrians and their equine counterparts. Properly preparing for the summer season by assessing your horse’s environment can make all the difference. Look for common allergens in their environment that can be eliminated before they impact your horse’s health. Practice good barn hygiene by managing dust levels and providing proper ventilation. Discourage insect populations by removing their breeding grounds. Most importantly, familiarize yourself with what your horse looks, sounds, and acts like when they are healthy so that you can quickly identify when something is off with your beloved friend. We all want our horses to look and feel their best, and planning ahead for the unique challenges that each season presents will set you up for success!


Michele Harn

Michele is a Contributing Writer for the Horse Review. She has been involved with horses in many different areas. At 4 years old, a Welsh pony started her on the road to riding and competing. Michele is experienced in Western, Saddle Seat, Barrel Racing, Dressage, Fox Hunting and Carriage Driving. She moved to the Mid-South from Wisconsin in the summer of 2021.

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