Common Horse Skin Conditions and How to Treat Them

Your horse is itchy, scabby, losing hair in weird patches, and you're standing in the barn aisle squinting at Google images trying to figure out what you're dealing with. Sound familiar? Skin problems are one of those universal horse-owner experiences, right up there with pulling shoes in the mud and discovering your horse rolled in something unspeakable five minutes before the vet arrives.

Quick Answer: The most common horse skin conditions (rain rot, scratches, ringworm, hives, and sweet itch) are usually caused by moisture, fungi, or insects, and most respond well to early treatment with proper hygiene and topical care.

Here's the thing about equine skin conditions: they all look annoyingly similar in the early stages. Hair loss, scabs, crusty patches, itching. Your brain screams "what IS that?" and honestly, sometimes even experienced horse people guess wrong. This guide breaks down the most common culprits, how to tell them apart, what actually works for treatment, and how to keep your horse from becoming a repeat offender. Because nobody wants to spend their entire summer budget on antifungal shampoo.

What Is Rain Rot and How Do You Treat It?

Rain rot. The skin condition so common it practically deserves its own fan club. If you've owned horses for more than a couple of seasons, you've probably dealt with this one already, and if you haven't, just wait.

Despite what the name suggests, rain itself isn't the villain here. The actual culprit is a bacterium called Dermatophilus congolensis that hangs out on your horse's skin, minding its business, until moisture gives it the green light to cause chaos. Think of it like that one friend who's totally chill until they have three drinks.

What It Looks Like

Rain rot shows up along the topline first: back, rump, neck. Basically wherever rain runs off the body. You'll spot small raised bumps or clusters of scabs, and when you pick at them (we all do it), they peel away with little tufts of hair attached, leaving raw pinkish skin underneath. These are often called "paintbrush" lesions because the hair tufts stuck to the scab's underside resemble tiny paintbrush tips. It can also pop up on the lower legs, face, or anywhere skin stays damp for too long.

Causes and Risk Factors

The Dermatophilus organism lives on many horses without ever causing trouble. It only becomes a problem when the skin's natural defenses take a hit, and prolonged moisture is the number-one trigger. Risk factors include:

• Extended exposure to rain or humidity without drying off
• Heavy winter coats trapping moisture against the skin
• Shared grooming tools, blankets, or tack spreading the organism between horses
• Insect bites breaking the skin's surface
• A compromised immune system from illness, stress, or poor nutrition

Treatment

Most rain rot cases clear up with straightforward at-home care, no vet visit required:

• Gently remove the scabs. The bacteria live underneath them, so this step matters. Soften scabs first with medicated shampoo or warm water, then carefully peel or brush them away. Dispose of them properly so other horses don't come in contact.
• Wash affected areas with antimicrobial shampoo containing chlorhexidine or betadine. Lather it up and let it sit on the skin for a full 10 minutes before rinsing.
• Dry the horse thoroughly. Cannot overstate this. The bacteria need moisture to survive, so cutting off their water supply is half the battle.
• Apply a topical antimicrobial spray after bathing. Chlorhexidine, betadine, or a dilute bleach solution (one part bleach to ten parts water) all work.
• Repeat every 2 to 3 days until scabs stop forming and healthy hair starts growing back. Most mild to moderate cases resolve within one to two weeks.

Severe or widespread cases might need systemic antibiotics from your vet. And if rain rot keeps coming back like a bad penny, dig deeper. There could be an underlying issue like Cushing's disease, immune compromise, or an environmental problem that needs addressing.

Scratches (Pastern Dermatitis)

Scratches goes by a dozen names: mud fever, greasy heel, pastern dermatitis. Whatever you call it, it's miserable for the horse and maddening for the owner. It hits the pastern and heel area hardest, and it loves horses with white legs, heavy feathering, or the misfortune of living in a swamp disguised as a paddock.

What It Looks Like

Early on, you'll notice redness, warmth, and sensitivity around the pasterns. Left unchecked, it progresses to crusty scabs, cracked skin, swelling, and sometimes a greasy or oozing discharge that will make you gag a little. In severe cases the skin thickens, becomes painful to touch, and the horse may go lame. It primarily affects the back of the pastern and heel bulbs but can creep up the cannon bone if you let it get away from you.

Causes

Scratches isn't a single-organism problem. It's a messy cocktail of bacteria, fungi, and sometimes mites all taking advantage of damaged skin. The common denominator is moisture. Contributing factors include:

• Wet, muddy paddock conditions
• Standing in damp bedding
• Frequent hosing of legs without proper drying afterward
• Feathered legs that trap moisture against the skin
• White or pink skin on the legs, which tends to be more sensitive
• Photosensitivity in some cases

Treatment

Treating scratches is a patience game. There's no overnight fix, so settle in:

• Clip the hair around the affected area if there's feathering or long hair. Air needs to reach the skin for anything else to work.
• Soften and remove scabs with warm water and antimicrobial soap. Work gently because this part hurts and your horse will let you know. Having someone hold the horse is a smart move.
• Wash with antimicrobial shampoo (chlorhexidine or betadine), let it sit for 10 minutes, then rinse thoroughly.
• Dry completely. Pat dry with clean towels, then let the area air-dry fully before applying anything.
• Apply a barrier cream or ointment. Desitin (zinc oxide), corona ointment, or prescription creams from your vet create a protective shield against moisture while treating the skin underneath.
• Keep the horse in a clean, dry environment during treatment. If the paddock looks like a rice paddy, the horse needs to come in until those pasterns heal.

Stubborn cases warrant a vet visit. Your veterinarian may prescribe oral or injectable antibiotics, anti-inflammatories, or do a skin scraping to check for Chorioptic mange mites, which can mimic scratches and require completely different treatment.

Ringworm (Dermatophytosis)

No worms involved. Zero. Ringworm is a fungal infection caused by dermatophyte fungi, most commonly Trichophyton and Microsporum species, and it spreads like wildfire through a barn. It can also jump to humans, so add that to the list of reasons to deal with it promptly.

What It Looks Like

Classic ringworm starts as small, circular patches of hair loss with crusty, scaly skin. The round shape is what gave this infection its completely misleading name. You'll often see it first where tack sits (girth area, under the saddle, around the head from shared halters) because contaminated equipment is a primary transmission route.

Here's a helpful distinguishing feature: ringworm lesions usually aren't itchy at first. As the infection spreads, patches may multiply or enlarge, and the center sometimes starts healing while the edges keep expanding, creating that signature ring pattern.

How It Spreads

Ringworm is wildly contagious. Transmission happens through:

• Direct contact between horses
• Shared tack, grooming tools, blankets, and halters
• Contaminated stall walls, fence posts, and other surfaces
• Human handlers carrying spores on hands and clothing

Fungal spores can survive in the environment for months. Months. So disinfection isn't optional; it's critical.

Treatment

• Isolate the affected horse immediately. No shared equipment between infected and healthy horses. Period.
• Clip hair around lesions so topical treatments can actually reach the skin. Bag up and dispose of the clipped hair carefully because it's loaded with fungal spores.
• Apply topical antifungal treatment. Miconazole or chlorhexidine-based washes work well. Enilconazole (Imaverol) is a prescription rinse commonly used for equine ringworm. Apply every 3 to 4 days for 2 to 3 weeks.
• Disinfect everything the infected horse has touched. Brushes, tack, blankets, stall walls. Dilute bleach solution does the job.
• Wear gloves when handling affected horses unless you want to explain circular rashes on your arms to your coworkers.
• Be patient. Most cases resolve in 4 to 8 weeks with consistent treatment. Hair regrows once the infection clears.

Stubborn or widespread infections may need oral antifungal medication from your vet, though that's typically a last resort.

Hives (Urticaria)

You walk out to the pasture and your horse looks like a lumpy potato. Raised bumps everywhere, coat standing up in weird spots, and you're immediately convinced something terrible is happening. Take a breath. Hives look dramatic, but they're usually harmless.

What It Looks Like

Firm, raised bumps (wheals) that range from dime-sized to several inches across. They appear suddenly and can spread across the body fast. The hair stands up over each bump, giving the coat a lumpy, uneven look. Most cases aren't painful, though some horses get mildly itchy or irritable about the whole situation.

Common Causes

Hives are an allergic response, and the list of possible triggers is long enough to make your head spin:

• Insect bites or stings
• New feed, supplements, or treats
• Medications, including vaccines and dewormers
• Contact with plants, chemicals, or new bedding
• Environmental allergens like pollen, dust, or mold
• Temperature changes
• Stress

Fair warning: you may never figure out the trigger. Horses are frustratingly good at developing allergies to seemingly nothing.

Treatment

• Remove the suspected trigger if you can identify it. New feed started this week? Pull it.
• Wait it out. Most cases resolve on their own within 24 to 48 hours.
• Cool water hosing can soothe irritated skin and bring some relief.
• Antihistamines like hydroxyzine or cetirizine may help, though their effectiveness in horses is honestly hit-or-miss. Your vet can advise on dosing.
• Corticosteroids from your vet may be warranted for severe or persistent outbreaks.

When to call the vet: Most hives are a non-event, but if you notice difficulty breathing, swelling around the nostrils or face, widespread leg swelling, or signs of distress, that's a potential anaphylactic reaction. Don't wait. Call your vet immediately.

Sweet Itch (Insect Bite Hypersensitivity)

If your horse rubs his mane and tail until they look like they went through a paper shredder, sweet itch might be your culprit. This allergic reaction to the saliva of Culicoides midges (those tiny biting gnats also called no-see-ums) is one of the most maddening conditions in the equine world because there's no cure, and affected horses are absolutely miserable without management.

What It Looks Like

Sweet itch targets the mane, tail head, and sometimes the face and belly midline, all the spots where Culicoides midges prefer to feed. Affected horses rub obsessively against fences, trees, stall walls, your truck, basically anything that doesn't move. The result is broken hair, bald patches, thickened skin, open sores, and secondary infections from all that self-inflicted trauma.

It's seasonal, peaking in spring and summer when midges are most active. In warmer climates it can drag on nearly year-round, which is just brutal.

Management and Treatment

No cure exists. This is a lifelong allergy, and management centers on reducing midge exposure and controlling the itch:

• Reduce midge exposure. Culicoides midges are most active at dawn and dusk, so bring your horse inside during those windows. Midges are weak fliers, so barn fans are surprisingly effective at keeping them away.
• Use a sweet itch sheet. These fine-mesh blankets cover the mane, body, and tail head, physically blocking midges from biting. They're one of the single most effective tools you can buy for a sweet-itch horse.
• Apply insect repellent with DEET or permethrin to exposed areas before turnout, especially during peak midge hours.
• Avoid turnout near standing water, marshes, or wooded areas where midges breed and swarm.
• Soothe the itch with medicated shampoos, topical lotions containing menthol or aloe vera, and soothing sprays. Some owners swear by coconut oil or tea tree oil-based products on affected areas.
• Antihistamines and corticosteroids may be prescribed for severe cases. Long-term steroid use carries side effects, so vets use them judiciously and reserve them for the hardest-hit horses.
• Omega-3 fatty acid supplementation (flaxseed or fish oil) can help dial down the inflammatory response over time.

Other Skin Conditions to Watch For

The big five above are the heavy hitters, but they're not the only skin issues you might encounter. Here are a few more worth knowing about.

Sarcoids

Sarcoids are the most common skin tumor in horses, thought to be linked to bovine papillomavirus. They range from small, flat, wart-like growths to large, angry masses, and their behavior is unpredictable. Some sit there for years doing nothing. Others grow aggressively and become a real problem. Treatment options include topical chemotherapy creams (like Liverpool cream), surgical removal, cryotherapy, and laser treatment. The right approach depends on type, location, and size. Definitely a vet conversation.

Melanomas

Got a gray horse? Keep an eye out. Gray horses are especially prone to melanomas: dark, firm lumps that typically show up under the tail, around the sheath or udder, on the lips, and near the eyes. Many grow slowly and stay benign for years, but they can become problematic if they enlarge or start interfering with body functions. Regular monitoring matters.

Photosensitivity

Some horses develop painful, sunburn-like reactions on white or pink-skinned areas after eating certain plants (St. John's wort and alsike clover are common offenders) or due to liver disease. Affected skin turns red, swells, and may blister or peel. Treatment means removing the offending plant, protecting skin from sun exposure, and addressing any underlying liver issues.

Warts (Papillomas)

Young horses under three sometimes sprout clusters of small, cauliflower-like warts on the muzzle, lips, and around the eyes. Equine papillomavirus is the cause, and these are almost always harmless. Most cases clear up on their own within a few months as the immune system kicks in. Treatment is rarely needed unless the warts interfere with eating or tack.

Prevention: Keeping Your Horse's Skin Healthy

Preventing skin conditions is infinitely easier (and cheaper) than treating them. These practices won't guarantee your horse never gets a funky skin thing, but they stack the odds heavily in your favor:

• Groom regularly. Daily grooming removes dirt, dead skin, and debris while boosting circulation. More importantly, it puts your hands all over the horse every day so you catch problems early.
• Keep living areas clean and dry. Damp, dirty conditions are ground zero for skin infections. Clean bedding, regular manure removal, and dry footing make a massive difference.
• Don't share grooming tools between horses without disinfecting first. So many conditions spread through contaminated equipment, and this is one of the easiest prevention steps to implement.
• Feed for skin health. Adequate protein, vitamins A and E, essential fatty acids, and trace minerals all support a strong skin barrier. If the diet is lacking, the skin shows it.
• Manage insect exposure. A comprehensive fly and insect management program is essential. Check our summer care guide for detailed strategies.
• Dry horses thoroughly after baths, rain, or heavy sweating. And never, ever leave a blanket on a damp horse. That's a rain rot invitation written in neon.
• Quarantine new horses for at least two weeks before herd introduction. Contagious conditions like ringworm need time to reveal themselves.

When to Call the Vet

Home treatment handles a lot of skin issues, but there are clear lines where professional help becomes necessary. Contact your veterinarian if:

• A skin condition hasn't improved after one to two weeks of consistent treatment
• The affected area is spreading rapidly
• Your horse is in significant discomfort (intense itching, pain, or lameness)
• Skin changes come with systemic signs like fever, lethargy, or appetite loss
• You spot any new or changing lumps, bumps, or growths
• You suspect ringworm (it's contagious and can spread to you)
• Scratches is causing significant leg swelling or lameness
• You're just not sure what you're looking at

Your vet can run skin scrapes, fungal cultures, biopsies, and other diagnostics to nail down the cause and prescribe targeted treatment. Use the Symptom Advisor to get initial guidance on what might be going on, and log any skin issues in your My Horse health journal to track patterns over time.

Skin problems come with the territory of horse ownership. They're common, they're annoying, and they're rarely as scary as they look at first glance. Catch them early, treat them consistently, keep things clean and dry, and you'll handle most of what comes your way without losing sleep. For more equine health topics, browse the full blog or dig into specific conditions in the Horse Encyclopedia.

Frequently Asked Questions

Can I use human antifungal cream on my horse's ringworm?

In a pinch, over-the-counter antifungal creams like miconazole (yes, the same stuff in athlete's foot cream) can work on small ringworm lesions. They're not ideal for large areas because you'd burn through tubes fast, but for a single small patch, they'll do until you can get a proper equine antifungal wash. Just make sure whatever you use doesn't contain added pain relievers or other active ingredients meant for human skin.

My horse gets rain rot every single winter. What am I doing wrong?

Recurring rain rot usually points to an environmental or immune issue rather than a treatment failure. Check the obvious things first: is the horse standing in wet conditions, wearing damp blankets, or sharing grooming tools with other horses? If the environment is solid and the problem persists, ask your vet about testing for Cushing's disease (PPID), which suppresses the immune system and makes horses more susceptible to skin infections. Nutritional gaps, particularly in zinc and copper, can also play a role.

How can I tell the difference between scratches and ringworm on my horse's legs?

Location and pattern are your best clues. Scratches almost always starts at the back of the pastern and heel area, with crusty, cracked, sometimes oozing skin. Ringworm tends to form more distinct circular patches of hair loss with scaly edges and can appear anywhere on the body, not just the lower legs. Scratches is also typically more painful, while ringworm is usually not itchy in the early stages. When in doubt, your vet can do a quick fungal culture or skin scrape to confirm.

Are sweet itch sheets really worth the money?

For a horse with confirmed sweet itch, absolutely. They're one of the most effective management tools available because they physically block the midges from biting. That said, fit matters. A poorly fitting sheet that rubs or gaps at the neck defeats the purpose. Look for fine-mesh designs specifically made for sweet itch (not just regular fly sheets) and make sure coverage extends over the mane, withers, and tail head where midges prefer to feed.

Should I be worried about catching ringworm from my horse?

You should be aware, not panicked. Equine ringworm can absolutely transfer to humans, usually showing up as itchy, circular red patches on your arms or wherever you've had skin contact with the infected horse. Wearing gloves during treatment, washing your hands and forearms thoroughly after handling, and changing clothes before touching other horses are simple steps that drastically reduce your risk. If you do pick it up, OTC antifungal cream typically clears it within a couple of weeks.

Last reviewed: March 2026

Sources

• Texas A&M College of Veterinary Medicine & Biomedical Sciences. "Equine Skin Conditions." vetmed.tamu.edu
• Merck Veterinary Manual. "Skin Diseases of Horses." merckvetmanual.com
• Cornell University College of Veterinary Medicine. "Equine Dermatology." vet.cornell.edu
• AAEP. "Skin Conditions in Horses." aaep.org
• Scott, D.W. & Miller, W.H. Equine Dermatology, 2nd Edition. Saunders, 2010.