Why does my horse have bumps or welts after being bitten by flies? | arlo.® Atlas

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Overview

Yes, fly bites can leave small bumps or welts on a horse. This is often a local skin reaction to the bite itself, especially in fly season when midges and other biting insects are active. In many cases it settles once the irritation eases, but there can be several possible causes, including sensitivity to bites, rubbing, or a skin reaction that needs more care.

Things To Check

1. Check where the bumps are appearing. Areas such as the belly, legs, neck, ears and face are often more exposed to biting insects.

2. Look at the skin closely for redness, heat, broken skin, scabs or discharge.

3. Note whether the horse is stamping, swishing the tail, rubbing or restless after turnout.

4. See if the bumps appear soon after turnout, grooming, exercise or time near wet or grassy areas.

5. Check whether other horses nearby are also being bothered by flies or midges.

6. Feel whether the area seems more sensitive, swollen or itchy than the surrounding skin.

7. Watch whether the welts are fading within a few hours or lasting longer and becoming more widespread.

Common Causes

The most common cause is a mild skin reaction to fly bites. Some horses get small raised bumps or welts because their skin is simply more reactive to insect bites.

Fly saliva and repeated biting can also trigger local irritation, especially if the horse has been bitten several times in the same area.

Rubbing, scratching or stamping after being bitten can make the skin look more raised or inflamed than the bite itself would suggest.

Less commonly, a horse may be more generally sensitive to insect bites or developing a seasonal skin issue that shows up more clearly during fly season.

What To Do

Check the skin daily for any change in size, spread or heat. If the bumps are mild, keeping the area clean and dry is often enough.

Try to reduce fly exposure by adjusting turnout timing, using shelter where possible and keeping the horse as comfortable as you can during peak insect activity.

Avoid over-rubbing the skin when grooming, as this can make the area feel worse.

If the horse is rubbing or stamping a lot, keep a close eye on whether the skin is breaking down or becoming more irritated.

If the reaction keeps coming back, seems to be getting worse, or starts affecting larger areas of the body, it’s sensible to speak to your vet for tailored advice.

Products That May Help

During fly season, some owners like to keep their routine simple and consistent with products that support day-to-day insect-season management and coat care.

Horse Fly Sprays & Summer Care

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