Why does my horse have thickened skin where flies keep biting?

Read time: 3 minutes

Overview

Thickened skin where flies keep biting is often the result of repeated irritation. In many horses, the skin reacts to constant fly bites by becoming a bit swollen, crusty, scabby or tougher in that area over time.

It can happen for a few different reasons, including simple fly irritation, a stronger skin sensitivity, or rubbing and scratching that keeps the area inflamed. You can often check the pattern at home and help reduce the trigger, but if the skin is very sore, spreading, or not settling, it’s worth speaking to your vet.

Things To Check

1. Look at when the thickened skin seems to appear or worsen, such as after turnout, at dusk, after exercise, or after grooming.

2. Check the area closely for redness, heat, scabs, small sores, broken skin, discharge or any signs that it’s been rubbed.

3. Notice whether your horse is stamping, twitching, swishing the tail, rubbing, or trying to bite at the area.

4. Check if the skin is limited to one spot or if there are similar patches elsewhere, especially on the face, belly, legs, mane or tail head.

5. Think about whether flies are particularly bad where your horse is kept, such as near muck heaps, standing water, windy shelters or still air in the stable.

6. See whether rugs, masks or other gear might be rubbing the same area and making the skin feel thicker.

7. Make sure the horse hasn’t had a recent cut, scrape or bite that could have become irritated by repeated scratching or fly attention.

Common Causes

The most common cause is repeated fly bites in the same place, which can leave the skin thickened and a bit rough as it keeps healing and getting irritated again.

Some horses are simply more reactive to fly bites than others, so the skin may swell or scab more easily even when the bites look minor.

Rubbing and scratching can also make the skin thicker. Once a horse starts itching, the area can stay inflamed even after the original bite has settled.

Sometimes a fly bite reaction can overlap with other skin irritation, such as sensitive skin, mild dermatitis, or irritation from tack, rugs or grooming.

Less commonly, a thicker patch can reflect a skin infection or another skin condition, especially if the area is painful, hot, oozing or getting worse rather than better.

What To Do

Start by reducing the fly pressure around the horse as much as you can. Good stable and field hygiene, fewer standing flies, and sensible fly-season routines often make a noticeable difference.

Keep the area clean and dry, and avoid harsh scrubbing. If the skin is already rubbed, gentle cleaning is usually better than over-washing.

Watch for patterns. If the thickening seems linked to certain times of day, turnout places or equipment, that can help you work out what needs changing.

If your horse is scratching, try to limit further irritation by checking rugs, masks and any tack or grooming habits that might be making the spot worse.

Take a photo every few days if it helps you monitor whether the skin is improving, staying the same or slowly becoming more inflamed.

If the skin looks increasingly sore, starts weeping, or the horse seems uncomfortable, don't just wait and see. A vet can help rule out a bigger skin problem.

Products That May Help

When fly bites are part of the problem, routine summer management can be easier with the right fly-season care items. This collection may be useful alongside normal stable and turnout routines.

Horse Fly Sprays & Summer Care

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