Horse Summer Sores

Understanding, Treating, and Preventing Horse Summer Sores

by | Aug 3, 2023 | Equine Health, Equine Treatment

Ah, those pesky summer sores, or as the boffins like to call them, Habronemiasis. A thorn in the side (or rather, the skin) of every horse owner when the sun starts shining. They’re not just your run-of-the-mill bumps and scrapes, oh no. These nuisances are a lovechild of a trifecta: our four-legged friends, a particularly troublesome stomach worm (the Habronema and Draschia species, no less), and an unwanted entourage of flies. The outcome? Persistent, stubborn skin lesions with an itch that’ll make your horse kick up a fuss and a special feature called proud flesh—sounds majestic but it’s far from it.

If you’re thinking, “It’s just a sore, right?”, well, think again. These nuisances are more than a mere fly in the ointment. They’re bad news for your horse’s health and comfort. Stomach worms can stir up a bit of trouble in the horse’s belly, but the real trouble starts when these microscopic gatecrashers invade fresh wounds or those damp spots on your horse’s body. That’s when you get a gnarly lesion that stubbornly sticks around for years, getting nastier if left alone. An ounce of prevention, in the form of a top-notch fly repellent like Farnam SWAT Fly Repellent Ointment, might just be worth a pound of cure here.

The Habronemiasis Lifecycle

So, how does this mess start? Let’s take a peek at the life of a stomach worm. Flies, being the uncouth creatures they are, pick up stomach worm babies from horse manure or other, shall we say, less than gourmet fare. They then kindly drop these near the horse’s mouth, who unwittingly swallows them. The wormlets then hitch a ride to the horse’s stomach and grow into big, bad adult worms over a couple of months. These adults then lay eggs, which get booted out with the horse’s manure, starting the whole wild ride again.

The plot thickens when these wormlets are dumped by flies into fresh wounds or moist areas of the horse’s body. In this alien environment, they can’t grow up into adult worms and start wandering aimlessly around the horse’s wound. This results in inflammation and severe itching that can drive your horse to gnaw at the lesion—making things even worse by encouraging proud flesh and slowing down the healing process.

These summer sores aren’t shy about making themselves known. They show up as non-healing lesions, with severe itching and a “greasy” look, complete with a bloody fluid seeping from the wound. They can appear anywhere on the horse’s body where a wound occurs, especially in moist areas like the lower abdomen, corners of the eyes, lips, or the prepuce, which are a regular smorgasbord for flies. Be proactive and use a reliable wound care product like Banixx Horse & Pet Care on minor wounds to stop them from evolving into summer sores.

Impact of Seasonality on Summer Sores

The prevalence of summer sores spikes during the spring and summer months. Why? Because that’s when the fly population booms. More flies equal more worm larvae, which in turn leads to a higher risk of infection for our equine friends. The rising thermometer and damp conditions are like Club Med for both flies and stomach worms, making summer sores a hot seasonal issue.

Here’s a twist, though: if you turn a blind eye, these sores can fade away in the cold winter months, giving a false sense of healing. But don’t be fooled. They’re likely to make an unwelcome comeback with the return of spring and the buzzing of flies. This on-off pattern highlights the need for consistent care and treatment all year round. Regular deworming with a powerful dewormer like Durvet Ivermectin Paste can help keep these pesky stomach worms in check throughout the year.

Related: The 7 Best de-Wormers for Horses

Treatment Approaches for Summer Sores

First and foremost, deworming is the superhero in this scenario. It helps us bid adieu to stomach worms, the villains that cause summer sores. Wondering what’s the superweapon here? Well, deworming pastes packed with Ivermectin or Moxidectin are the way to go, folks. There are a couple of reliable options out there like Durvet Ivermectin Paste Equine Dewormer and Quest Plus Gel Moxidectin Horse Dewormer.

But let’s say the sores are a bit more stubborn, and you’re dealing with severe cases. These sores have developed a chunk of proud flesh that’s tough to deal with. In that case, you might need to roll up your sleeves for a surgical removal before you can start the deworming process. Post-surgery, a dash of a concoction made from glucocorticosteroids and DMSO (dimethyl sulfoxide) should be lathered on the sore. This mix helps reduce inflammation and itchiness, kind of like a soothing balm. Products like Betadine Solution also work wonders for this purpose.

And guess what? Sometimes, you may have to swaddle the sore, especially if it’s on the horse’s legs. This helps protect the wound and also prevents your horse from aggravating it by chewing.

For more advanced cases, our arsenal includes antibiotics and corticosteroids that can be given orally or via injections. Prescripption meds like Triamcinolone acetonide can be your go-to, consult your vet. Then there’s this super cool method – Cryotherapy. Sounds scientific, right? It’s just freezing the lesion with liquid nitrogen. Quite effective for some severe cases.

Prevention Strategies

Now that we’ve talked about treating summer sores, let’s discuss some prevention tactics. The mainstay here is fly control. Yup, keeping those pesky flies at bay is crucial. Here’s how we can do it:

1. Cleanliness is godliness, as they say. Regularly removing manure and excess feedstuffs can significantly keep the fly population in check.

2. Compost piles should be well managed, cranked up to maximize heat production. Why, you ask? Well, the heat wipes out those hatching fly maggots. Neat, huh?

3. We can also use parasitic wasps as biological control agents. These beneficial insects, like Fly Predators, are pretty good at controlling the fly population.

4. Insecticides, fly traps, baits, residual fly sprays, and repellents – they all come in handy. For instance, the Farnam Endure Sweat-Resistant Fly Spray for Horses is a reliable product.

5. Feeding horses with insect growth regulators (IGRs) can nip the problem in the bud. Products like SimpliFly with LarvaStop, an IGR, can keep the development of flies in the manure at bay.

A few other prevention measures include regular cleaning and removal of waste from stalls and paddocks. It’s a dirty job, but it helps prevent the spread of those darn stomach worm larvae. To make this easier, the Dover Saddlery Fine Tine Fork can be a reliable tool.

Keeping flies away physically can also be a great help. Using fly masks and sheets, like the Cashel Crusader Fly Mask, can do the trick. And let’s not forget, regular health checks and maintaining a deworming schedule can also keep those annoying summer sores away.


At the end of the day, it’s about understanding, treating, and preventing summer sores to keep our horses healthy and happy. After all, their wellbeing is our priority. Armed with the right knowledge and effective strategies, we can ensure our horses lead comfortable lives. Let’s make this a responsibility as horse owners, veterinarians, and caregivers, for the sake of these magnificent creatures.

About The Author

<a href="" target="_self">Emily Wilson</a>

Emily Wilson

I'm from the very heart of Kentucky, you know, the place folks think of when they talk about horse love. Had the luck of growing up smack dab in the middle of some of the most awesome horse spots you'd ever see. Can't imagine starting my day any other way than being in that homely barn, waist-deep in horse stuff. My routine? It's a bit of everything really - taking care of the horses, bonding with them, you name it.

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