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What is Mosquito Bite Allergy?

Your horse will have an allergic reaction to the mosquito bite and can develop hair loss, hives, itching and crusting over the affected area. The saliva of the mosquito causes an inflammatory reaction and is very common when mosquitoes are active in your area. 

Insect control will be essential if your horse has an allergy to mosquitoes. This can include spraying your property with a broad spectrum insect repellent, installing bug zappers or other insect traps and applying insect repellent directly on your horse.

An allergy is simply a response from the immune system to a substance within the environment. These substances that cause a reaction are known as allergens. You generally do not think of mosquito bites as being allergens, but in some cases, horses will have an allergic reaction to a mosquito bite. This allergy is considered to be part of insect bite hypersensitivity or sweet itch.

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Symptoms of Mosquito Bite Allergy in Horses

If you notice your horse acting oddly or profusely rubbing specific places of their body, you should contact your veterinarian for an assessment. Remove your horse from their pasture and put them in their stall to minimize exposure to mosquitoes and other biting insects. Symptoms of mosquito bite allergy to look for include:

  • Hair loss
  • Swelling 
  • Itching
  • Crusting of the affected area
  • Profuse rubbing or biting 
  • White hairs developing at the site of the bite
  • Rat tail or breakage of the tail hairs

Causes of Mosquito Bite Allergy in Horses

Mosquito bite allergies in horses can be a common occurrence, especially in the summer months or in areas where there is standing water. Just like in people, mosquitoes can cause hives to appear when they bite. Horses with an allergy to mosquitoes will react when the saliva of the mosquito touches their skin. Intense itching can occur and hair loss from rubbing or biting the affected area. 

Prevent mosquitoes from biting your horse by using a mosquito repellant. You can also use bug zappers around your property to deter mosquitoes from biting your horse. Keep any standing water from accumulating on your property so mosquitoes do not freely breed near your horse.

Diagnosis of Mosquito Bite Allergy in Horses

Your veterinarian will begin by taking a full medical history on your horse and conducting a physical examination. They will pay close attention to any areas of hair loss or any present hives. 

A complete blood count, urinalysis, and fecal examination may also be done to eliminate other possible problems that can cause the same symptoms. A skin scraping may also be done to look for mites, fungus, parasites or other skin conditions. 

Your veterinarian may do a walk through of your property, looking for anything that might be causing the irritation. Mosquitoes are especially active at dusk so relay to your veterinarian if you have noticed an influx of mosquitoes on your property recently.

Treatment of Mosquito Bite Allergy in Horses

Your veterinarian will prescribe a topical cream, usually a corticosteroid, to alleviate the itch of the mosquito bite allergy. Your veterinarian will also recommend a repellent spray to be applied directly to your horse. If the allergic reaction is severe, your veterinarian may give a steroid along with antihistamines such as pyrilamine or hydroxyzine. 

Some veterinarians may also recommend supplementing your horse with Omega 3 fatty acids. Specifically feeding a flaxseed supplement for mosquito bite allergy has shown a significant decrease in the allergic response. These will help reduce the inflammation from the mosquito bites. 

There are other supplements that may also help your horse’s immune system fight off the allergic reaction to mosquito bites. Those include MSM, probiotics and probiotics and adaptogens. Brewer’s yeast, garlic and apple cider vinegar have been known to keep mosquitoes from actually biting your horse. 

You may also be able to do hyposensitization therapy. This is a series of allergy shots that will expose your horse to the allergen and hopefully allow them to form immunity to the allergen.

Recovery of Mosquito Bite Allergy in Horses

Your horse’s prognosis is fairly good when they are diagnosed with mosquito bite allergies. After the initial diagnosis, your main goal will be to keep mosquitoes from biting your horse. 

Remove all standing water from your property and install bug deterrents, especially near your horse’s pasture and barn. Invest in a good insect repellent to spray around your property. Ask your veterinarian about which insect spray to use on your horse and apply near dusk when mosquitoes are most active. Feed your horse supplements that include garlic, brewer’s yeast and/or apple cider vinegar; these are all known to keep insects from biting.