Spring means shedding season is wrapping up, the pastures are green, and your horse is finally starting to look like themselves again. But it also means the threats are coming — and they come fast.
Between the biting insects, the humidity, the standing water in pastures after a good rain, and the sweat under tack, your horse's skin and coat are about to take a beating. The damage doesn't always show up overnight. It builds. A little rubbing here, a dull patch there, and before you know it you're dealing with a full-blown skin issue that takes weeks to resolve.
The good news? Most of it is preventable. You just need to know what you're defending against and when to act.
The Two Big Seasonal Threats
Spring and summer skin problems in horses fall into two categories: insects and moisture. They're different problems, but they overlap more than most people realize — and they often show up at the same time.
Insects: More Than Just an Annoyance
Biting insects aren't just irritating to your horse — they cause real, measurable damage to the skin and coat. No-see-ums (Culicoides midges), black flies, horse flies, mosquitoes, and stable flies all feed on your horse's blood, and the allergic reaction to their saliva is what causes the itching, rubbing, and hair loss that follows.
The worst part? Some horses develop sweet itch — a hypersensitivity to insect saliva that turns a few bites into an intense, relentless itch. These horses rub their manes and tails raw, lose patches of hair, and develop thickened, damaged skin that takes months to recover even after bug season ends.
No-see-ums are the biggest culprits because they're small enough to get through most fly sheets and feed during dawn and dusk when your horse may not be protected.
What to watch for:
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Rubbing along the mane line, poll, or tail base
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Small crusty welts, especially along the belly and under the jaw
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Hair loss or thinning in patches
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Restlessness, stamping, or tail swishing that goes beyond normal
What actually helps:
A good insect defense strategy starts with a quality coat spray — but not all sprays are created equal. Most commercial fly sprays use synthetic pyrethroids that evaporate quickly, require constant reapplication, and can irritate already-sensitive skin. Oil-based formulas last longer because they create a physical barrier on the coat rather than just sitting on the surface.
No-See-Um Coat Spray uses a blend of natural oils that repel biting insects while conditioning the coat at the same time. The oil base means it doesn't evaporate in twenty minutes like water-based sprays, and it won't dry out the skin with repeated use. Apply it before turnout — especially at dawn and dusk when no-see-ums are most active — and focus on the areas insects target most: mane line, belly, inner thighs, under the jaw, and around the ears.
Moisture & Fungal Issues: The Quiet Damage
While insects get all the attention, moisture-related skin problems are just as common in spring and summer — and they're sneakier. These issues develop slowly, often hidden under the coat until they've already spread.
Here's what creates the perfect storm:
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Rain and humidity keep the skin damp for extended periods
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Sweat under tack creates a warm, moist environment bacteria and fungus love
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Morning dew on pasture soaks the lower legs daily
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Standing mud and water softens the skin barrier
That combination gives you the big three warm-weather skin conditions: rain rot (dermatophilosis — a bacterial infection that causes crusty, paintbrush-like scabs along the back and hindquarters), scratches/mud fever (pastern dermatitis from chronically wet lower legs), and fungal infections that show up as circular patches of hair loss, flaking, or dull coat.
What to watch for:
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Scabby or crusty patches along the topline, back, or rump
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Flaky, irritated skin around the pasterns or heels
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Circular bald patches that aren't from rubbing
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A coat that looks dull or rough despite good nutrition
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Sensitivity when grooming certain areas
Building a moisture defense routine:
Prevention comes down to keeping the skin clean and dry, and supporting the skin's natural defenses when you can't control the weather.
After rainy days or heavy sweating under tack, take the time to dry your horse's skin — especially along the back, girth area, and lower legs. A clean towel and five minutes of attention can prevent a week-long skin issue.
For horses that are prone to fungal issues, moisture-trapping conditions, or pastern dermatitis, a talc-free anti-fungal grooming powder makes a real difference. Restorative Powder is designed specifically for this — it absorbs excess moisture, supports the skin's natural healing process, and creates an environment where fungus and bacteria struggle to take hold. Dust it into areas that stay damp: between the heels, along the girth line, under the jaw, and anywhere tack sits against wet skin.
The key word there is preventive. Don't wait for the scabs to show up. If you know your horse is standing in wet pasture every morning or sweating heavily under tack, work the powder into your routine before the problems start.
A Simple Spring & Summer Skin Care Routine
You don't need a complicated system. Here's what a solid warm-weather routine looks like:
Before turnout (especially dawn/dusk): Apply No-See-Um Coat Spray to insect-target zones — mane, poll, belly, inner legs, ears, tail base. Reapply after rain or heavy sweating.
After riding or sweating: Towel-dry under the saddle area, girth, and anywhere tack held sweat against the skin. If your horse is prone to fungal issues, dust Restorative Powder into those areas while the skin is clean and dry.
After rain or wet pasture: Check and dry the pasterns, heels, and lower legs. Apply Restorative Powder to moisture-prone areas. Inspect the topline for early signs of rain rot — catching it in the first day or two makes a world of difference.
Weekly grooming check: Run your hands over the entire body. Feel for scabs, bumps, rough patches, or areas of heat. Check the mane and tail base for rubbing. Catching problems early means solving them in days instead of weeks.
When Prevention Isn't Enough
Sometimes despite your best efforts, something breaks through. A few days of heavy rain, a missed application, or a horse that's just more sensitive than the rest of the herd.
If you're dealing with an active skin issue — rain rot that's already scabbed over, fungal patches that are spreading, or insect-bite damage that's broken the skin — the approach shifts from prevention to recovery. Don't pick scabs (it spreads the infection and damages healing tissue). Gently soften and remove them with a medicated wash, dry the area thoroughly, and support the skin's recovery with Restorative Powder to keep the area dry and protected while it heals.
For deeper dives on specific conditions, we've written detailed guides on each one:
Frequently Asked Questions
What's the best way to protect my horse from no-see-ums and biting insects naturally? An oil-based coat spray creates a longer-lasting barrier than water-based fly sprays. Apply before turnout — especially at dawn and dusk — focusing on the mane line, belly, inner thighs, and ears. Combine with management strategies like fans in stalls and avoiding turnout during peak feeding hours.
How do I prevent rain rot and fungal skin issues in humid weather? Keep the skin clean and dry. After rain, sweating, or wet pasture exposure, towel-dry moisture-prone areas and apply a talc-free anti-fungal powder to absorb moisture and discourage bacterial and fungal growth. Don't leave sweat-soaked tack pads on the horse after riding.
Can I use insect spray and anti-fungal powder at the same time? Yes. They work on different problems and complement each other well. Apply the coat spray to exposed areas for insect defense, and use the powder in areas that trap moisture — under tack, between the heels, along the girth line. Together they cover both major seasonal threats.
My horse is already rubbing his mane and tail — is it insects or something else? Mane and tail rubbing is most commonly caused by insect hypersensitivity (sweet itch), but it can also be triggered by dry skin, pinworms, or contact irritation. If the rubbing is worst during dawn and dusk and concentrated at the mane and tail base, insects are the most likely cause. Check our full guide on mane and tail rubbing for a complete breakdown.
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