Insect bite hypersensitivity
Tuesdays with Tony
Ah, Florida. We have a lot of fun stuff here… beautiful beaches and great places to ride your horse. You know what we also have in plenty? Bugs. Yep, I’m sure you have noticed the bugs. Between the heat, the humidity, and the bugs, Florida in summer can be kinda hard on your cat. I mean horse. Hard on your horse.
As the Springhill cat, I like to spend time laying on the bench outside the clinic, but when I’m ready to take a break from Florida summer I just stare at the clinic door until my minions let me in. Unfortunately, it’s not as easy for your horse to escape the flies and gnats that are part of our summers. Have you noticed that some horses have a much harder time of it than others? They itch themselves like crazy, they scratch their mane and tail out, their ears are rubbed raw, and they just look miserable.
So why does one horse look awful while the rest of the herd is doing fine? Because that poor itchy horse is allergic to the bites of insects, specifically their saliva, making him hypersensitive to its effects. Insect bite hypersensitivity (also called seasonal pruritic dermatitis) causes intense itchiness, hair loss, and abrasive skin damage. It’s usually caused by gnats, flies, or mosquitoes, though any biting insect can be the culprit. The most common locations you’ll see skin lesions are the ears, the face, the bottom of the belly, and the tail head, though badly affected horses can have bumps and hair loss all over their body.
To get your itchy horse some relief, my docs recommend a combination of strategies.
Decrease your Horse’s Exposure to Insects
Keep his environment as clean and free of manure as you can. Removing manure and standing water will help to decrease fly populations. A feed-through fly inhibitor can also reduce the number of flies breeding on your property, though it is really only effective if every horse on the property is on it. These products are often easily available at your local feed store.
You may need to stable your horse to avoid the times when gnats are most active – that’s at dawn and dusk. Box fans in the stall are useful because gnats aren’t very good fliers and will avoid a strong air current. Fly sheets and fly masks (the kind with ears) can help. You can apply fly spray, but it doesn’t usually last long and is rarely effective by itself.
Omega-3 Fatty Acid Supplements
These healthy oils help to decrease inflammation in the skin and promote a healthy hair coat. They can be very beneficial for horses with insect hypersensitivity and other types of allergies. Ground flax seed is a good source of Omega 3s, such as Triple Crown Naturals Golden Ground Flax.
Bathing and Topical Products
Bathe your horse at least once a week during insect season. Colloidal oatmeal or hydrocortisone shampoos can reduce the itch and soothe the irritated skin. My docs really like the Equishield products – they make a great shampoo called IR, for itch relief. In between baths, cool water rinses can reduce the sweat, irritants, and allergens on his skin.
Equishield IBH salve works great for those focal areas where your horse needs extra help – like his ears and face. It helps to soothe the itch as well as repel the bugs. For larger body areas, or places with thick hair like the mane and tail head, the IBH spray works best. These products are an important part of our summer arsenal, and we’ve got a good supply here at the Clinic if you need some.
Medications
The allergy can be so bad that some horses need to be placed on a steroid during the insect season to break the itch cycle. Steroids are effective, easy to administer, and relatively inexpensive, but they have to be used with caution. The goal of the bathing, supplements, and insect control I just described is to reduce the need for steroids as much as possible. But when a horse really needs them, these medications can really help that poor horse get some relief. Antihistamine medications may be used as well, but alone they’re often not effective.
Most horses with insect bite allergy can be managed with a combination of these lifestyle and medication strategies. So if your horse is itchy, bumpy, crusty, or looks like a moth-eaten sweater during our lovely Florida summers, give my docs a call!
Until next week,
~ Tony
P.S. There’s a new video out on my YouTube Channel, make sure you go check it out!
Tuesdays with Tony is the official blog of Tony the Clinic Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at SpringhillEquine.com, or follow us on Facebook!
Culicoides (kyōō′lĭ-koi′dēz′) is a species of gnat very common here in Florida. Many horses are actually allergic to the saliva of this gnat, so every bite by one of these annoying little devils sends the poor horse into an itching frenzy. The early signs of this gnat allergy include frequent scratching and hair loss in the ears, mane, base of tail, and chest. Over time the skin in these places will become thickened, there will be multiple open bite wounds, the hair will be completely gone, and the horse will constantly be scratching on anything and everything he can find. Horses with chronic Culicoides hypersensitivity will often develop a “cauliflower ear” appearance over a period of years. Once this happens, the ears will never return to their original shape.
Once the ear has gotten to a point where there is a secondary laceration, abscess, or hematoma, it can be difficult to treat. While we always try conservative options first, these horses sometimes have to undergo surgery under general anesthesia to drain the ear, followed by weeks with the ear taped down against the horse’s head to allow for continued drainage. No fun.
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