Why does sweet itch seem worse after rain?

Read time: 3 minutes

Overview

Sweet itch can seem worse after rain because damp skin, higher humidity and the change in weather can make horses more uncomfortable and can also bring biting insects back out again. It doesn't always mean the condition has suddenly changed, but it does usually mean there are a few things worth checking around turnout, coat condition and insect pressure.

Things To Check

1. Check whether the itching starts or gets worse after rain, after turnout, or when the horse is brought back in.

2. Look closely at the mane, tail head, dock, belly and ears for rubbing, scabs, broken hair or sore skin.

3. Feel whether the coat or skin is still damp under rugs, around the mane or in areas where rain runs off.

4. Notice whether there are more midges, flies or other biting insects around after the rain stops, especially at dawn and dusk.

5. Check whether rugs, masks or other fly gear are rubbing more when wet, loose, or dirty.

6. Think about whether the horse has been sweating as well as getting wet, because dampness and heat together can make skin feel more irritated.

7. Watch for any pattern with pasture, shelter use or standing water nearby, since these can all affect insect levels.

Common Causes

The most common reason is that rain changes the skin environment. Dampness can make already-irritated skin feel more uncomfortable, especially if the coat stays wet for a while.

Another common factor is insect activity. Rain often doesn't remove the problem for long, and once the weather clears, midges and other biting insects may be more noticeable around the horse.

Wet rugs, dirty fly masks or damp saddle and grooming areas can also make rubbing and skin irritation more likely.

Less commonly, a horse that seems worse after rain may also have another skin issue alongside sweet itch, such as simple rubbing, a mild skin infection or sensitivity to mud and damp around the lower body.

What To Do

Start by keeping a note of when the itching is worse, where the horse rubs and what the weather was doing. That makes it easier to spot patterns.

Try to keep the skin as dry and clean as you reasonably can, especially around the mane, tail and under any rugs or fly protection.

After rain, check that any rugs, masks or neck covers are dry, clean and not causing rubs. If they are damp or dirty, swap them out if you can.

Reduce insect exposure where possible by avoiding peak biting times, using shelter if available and keeping turnout management as consistent as you can.

If the skin is being rubbed raw, if scabs are spreading, or if the horse is becoming increasingly distressed, it’s sensible to ask your vet for advice.

Products That May Help

For horses that need extra help staying comfortable through fly season, a collection built around seasonal insect and itch management may be useful as part of your routine care.

Horse Fly Sprays & Summer Care

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