Skin Problems in Horses


I’ll be the first to admit that it’s quite fun to say “fungus amongus” when describing any skin funk we find on our horses. Chances are, it’s not a fungus but one of many other causes.  Because why would it be that simple? Start to ramp up your detective skills when it comes to skin problems in horses!


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Anatomy of the horse’s skin


  • The horse’s skin is a wonder of science. It’s not just pretty wrapping paper on your horse; the skin is part of your horse’s immune system!



The outermost layer is the epidermis


  • The epidermis is a physical barrier to the outside world. It’s thick with layers of different types of cells. Keratinocytes make new skin cells at the base of the epidermis. Fresh cells work their way to the surface and eventually slough off.


  • Other types of cells in the epidermis make pigment, and some are reactionary to immune threats, as in the case of a rash. Don’t forget about vibrissae, the tactile hairs like whiskers and eyebrows that help your horse feel the world. Vibrissae have their own set of skin cells to help with sensations.


horse resting in pasture with front legs tucked in

Resting his skin in the sunshine.


The middle layer of the skin is the dermis


  • The skin’s blood supply and nerve supply are here! The dermis also houses collagen and elastin, providing strength and flexibility to the skin. As everything ages, this is what starts to lose elasticity. Thanks so much, aging!


  • The dermis also has a layer of immune cells to attack infectious agents should they break through the epidermis.


  • Hair follicles, sebaceous glands, and sweat glands also being in the dermis. Sebaceous glands are attached to the hair follicle and secrete sebum. This miracle substance is a shine booster, and it’s anti-microbial. SO YES – your horse’s natural oils have an important job!


The subcutaneous layer of your horse’s skin is the last portion.


  • Here, the skin has muscle, fat, nerves, and blood vessels. It can also store electrolytes, and those muscle and fat cells act as a shock absorber.


Causes of skin problems in horses


Backing up a quick sec, let’s look at big-picture issues that affect the skin.


  • Is your horse healthy overall? We all like to think so, but all sorts of disorders, like metabolic issues and allergies, take a toll. Don’t forget about your horse’s fitness level. This is part of his overall health, too.


  • How is your horse’s diet? Creating a proper and balanced diet for your horse is perhaps the most confusing thing ever. It can change seasonally, with new cuts of hay, new barn locations, and any health issues that pop up or disappear.


  • Are you a horse owner who grooms judiciously or cuts corners a little too often?  In many cases, more is definitely better here.


  • How do you feel about detergents and shampoos? The key to a shiny horse is sebum! Over-shampooing strips all of that sebum away. The healthy anti-microbial oil is gone, his hair is brittle, stains get glued in, and the shine has vaporized. This may contribute to skin issues!


  • When was your horse’s last fecal egg count? Large parasite infections contribute to a dull coat in horses. Regular fecal egg counts and deworming with your vet’s guidance are key here. Gone are the days of alternating dewormers! Many internal parasites are becoming resistant to dewormers. Willy-nilly giving them without an actual need to creates this resistance. Anyway, my point is that inside health shows up on the outside.


vet truck

Call the dang vet!


What’s the plan when you spot something abnormal on your horse’s skin?


  • Approximately 3,764,023,496 different things cause skin stuff. Your quick internet search will reveal just as many “solutions.” The only way to get a quick resolution is to work with your vet to figure out the actual cause from the beginning.


  • Using a targeted treatment from the get-go increases your chances of a much smaller vet bill. Not to mention increasing your horse’s chance of a speedy recovery.


  • If there are underlying issues to your horse’s particular skin disease, your vet can also help you address those.


Overview of typical skin problems in horses 


Equine pastern dermatitis (EPD)


  • EPD is the umbrella term for all sorts of lower leg skin infections.


  • EPD is a syndrome, not a definitive diagnosis. It covers skin conditions on the legs involving hair loss, blisters, lameness, redness, thickening skin, sores, scabs, lizard-like skin, and even oozing. The kicker about EPD is the same as the kicker for all skin problems – you gotta know what’s going on to get the best treatment.


  • Scratches, mud fever, and dew poisoning are the same way to describe the lower legs’ bacterial infection that falls under the EPD umbrella.


Read more about equine pastern dermatitis and see some pretty gross photos. Don’t worry; the images are at the bottom, and viewing is optional.


sox for horses on horse leg with black hoof

Horse socks can be helpful when trying to keep dirt and bacteria and “stuff” out as your horse’s leg heals. These are the Silver Whinny’s from Sox for Horses.


Rain rot.


  • While we like to think of rain as the culprit here, it’s bacteria. Commonly associated with humid conditions, the bacteria set up shop and create scaly patches of skin with tufts of hair coming out. This can escalate to bald patches and secondary infections.


  • Most cases of rain rot, AKA rain scald, will clear without your vet’s help. However, you need to keep the skin clean and dry. Rain rot will jump from horse to horse with shared tack and grooming supplies.



bad rain rot on a horse butt cheek

Classic rain rot!




  • A real fungal infection, ringworm looks like circular-ish patches of hair loss. It’s also contagious; people can even pick it up from our creatures. Sometimes, localized ringworm is all you need to worry about. Other times, it’s a bit more systemic. Like rain rot, ringworm thrives in damp areas. Like a mucky winter coat!


  • The fungi that cause ringworm eat keratin! As in the keratin that makes up your horse’s hair. With your horse’s vet, clip the area, and keep it clean and dry. Your horse will likely need prescription meds.




  • Elementary school flashbacks, anyone? Lice, a parasite, can infect horses! And you can see them. When lice take up residence in your horse’s mane, tail, and lower legs, it’s called pediculosis. Lice usually infect sick, older, or immunologically compromised horses.


  • A horse might be infected with sucking lice. These buggers eat blood from the roots of your horse’s hair! Sucking lice are about 2mm long and don’t move around much.


  • Chewing lice eat your horse’s dander and often venture away from the mane and tail to softer body hairs. They are smaller than their sucking cousins.


  • Unluckily for horses, there can be horse-to-horse transmission if an infected horse rubs the lice eggs off, and another horse comes along and rubs there, too. Humans, luckily, are not delicious enough for these types of lice.


mite photo up close to show legs and body

This is some sort of mite and I’ve seen all I want to see. BLECH


Mites and mange


  • These jerky bugs attack your horse’s skin and are too small to see. Mites come in a few varieties that eat horses and end up with mange. Yes, the same thing that causes hairless scabby skin in dogs.


  • Chorioptic mites, AKA feather mites, live around the horse’s legs. They eat skin, fat, and even the sores that they make become their next meal. Your horse will be unbelievably itchy and may chew himself. You can pass this to other horses with shared tools, but you are safe.


  • Psoroptes mites, AKA scab mites, create sores and scabs. Then, they poop, and your horse has an allergic reaction to the mite poop. This makes your horse develop oozing skin, which eventually hardens and loses its hair. Yes, sharing grooming tools can spread this.


  • Don’t feel left out! The Sarcoptes mite will jump ship from horses to humans. Their saliva creates a massive skin reaction when they eat your horse’s skin. There may be pimples and massive thickening of the skin. It’s also wildly itchy and can be anywhere on your horse. Secondary infections are possible when your horse scratches himself and creates more damage.


  • And finally, the Demodex mite hangs out in the hair follicles. They make a horse’s skin scaly, and they like to travel all over your horse’s body.


  • Because mite infections can look like other things, your vet needs to be in the loop. Treatment for mites takes a long time, and the skin needs to heal for the hair to return.


Aural plaques


  • If you ever find a weird scaly patch that looks like dried-up cauliflower in the ear, it might be an aural plaque.


  • There are unknowns about aural plaques. A papilloma virus causes them, but the transmission may, or may not, be fly related. Some horses are not bothered at all by aural plaques, and others are most definitely concerned.


  • Sometimes plaques clear up; sometimes they don’t. Aural plaques can be small or large but typically remain inside the inner ear.


  • Your vet does have a few treatment options, but they can be painful. The topical medications often create more swelling and irritation.


aural plaques in a horse ear

Photo by Monica D. (Thanks!)




  • Sarcoids are tumors of the skin, also spread by a papilloma virus. They are technically benign as they don’t spread to other locations on a horse. But, they can be uncomfortable and grow large. Sarcoids often interfere with tack and blankets. If a sarcoid is near the eyes, it might interfere with the eyelids. These tumors can also break open!


  • Treat sarcoids early. Surgery and topical medications remove these tumors, with better results when the tumors are small.




  • If this isn’t the biggest can of worms with horses, I’m not sure what is. Horse allergies are vague to spot, tricky to narrow down, and affect horses differently.


  • Insect bites, hay, fly sprays, grooming products, blanket fabrics, and even treats can trigger horses’ allergies. How they present is another story. Diarrhea, itchiness, and welts are all possible ways your horse tells you he’s allergic to something. Thanks, horse. Isn’t it just easier to text us?


  • Treatments for allergies vary, depending on the triggering allergen. You might need to change detergents for horse laundry, change a part of your horse’s diet, or try other brands of grooming products.


Sweet itch


  • Midges cause his annoying skin condition. Culicoides midges, about 4mm long, bite your horse along his topside, anywhere from ears to tail. Some horses are highly allergic and begin to itch wildly. They are scratching to the point of breaking their skin open.


  • Then the midges bite again. Things try to heal, but scabs get removed because of the itching and scratching cycle. It’s a huge, hot mess.


  • Sweet itch is a battle of boundaries – and the solution is covering your horse up with special sweet itch sheets. Tweak your horse’s turnout time to avoid dawn and dusk, the busy time of day for midges.


horse in sweet itch blanket




  • Plain ol’ dry skin is usually the culprit for dandruff. As a horse’s skin grows and sheds, dandruff may happen. It can be normal for a horse, a sign that something else is wrong, or a result of an incomplete diet. Sometimes liver and other internal problems will create dandruff.


  • You can find dry dandruff and oily dandruff. Oil dandruff may be the result of mites or lice.


  • Depending on the cause of dandruff, you might need a special shampoo. Or a prescription for lice treatment. Or bumping up your horse’s diet to include more skin-healthy ingredients, like Omega-3 fatty acids.




  • Anhidrosis is a skin disorder of horses and happens when a horse can’t fully sweat or can’t sweat at all. Yes, this is bad and can quickly overheat a horse in the summer.


  • So much about anhidrosis is a mystery. Sometimes it appears from the ether. Other times a horse can have it for years, and then he can sweat normally again.


  • To help the horse with anhidrosis, exercise him when it’s coolest outside. Use alcohol sprays to help his body thermoregulate, and look into supplements and medications from your vet.


Girth galls


  • Galls are the old-school way of describing a girth or saddle sore. They begin as a patch where you might see some hair loss or breakage.


  • As friction between tack and skin continues, the hair can rub entirely away, and sores open up. Galls are part skin issue and part tack issue!


  • Your vet can help you heal the wound. Make some changes to your tack before you ride again. Girths come in all shapes, and girth covers might also work to alleviate some friction. Check-in with your saddle fitter if the sores are higher up.


girth gall covered with zinc oxide cream

This is the usual spot for girth galls.




  • Photosensitivity is a fascinating skin problem that happens from things going on inside your horse’s body. When horses eat certain weeds, they release photosensitive compounds in your horse’s body, which create blisters and sores when exposed to UV light. Some liver diseases manifest this way, too.


  • Photosensitive horses are in pain, and it often looks like scratches or dermatitis. You will usually see the sores on pink skin under truly white hair.


  • Finding the cause and ruling out liver damage is the first step. Then, protect your horse from UV rays. Most photosensitive horses do not want to be in the sun!


horse legs in the shade with lots of chrome white stockings

True white hair and pink skin can be photosensitive.


Proud flesh


  • Oh, what a nightmare proud flesh can be. This overgrowth of granulation tissue can quickly take over a horse’s lower leg! Granulation tissue is the blood-rich pink tissue that close the edges of a wound and bring the skin back together. Proud flesh happens when that granulation tissue goes into a hyper-drive mode.


  • Your veterinarian may need to do surgery for this, and caring for a wound with proud flesh is an investment of time and multiple veterinary interventions.


How to notice common skin conditions


  • There is no better preventative for any problem than daily horse grooming. Curry combing is vital for keeping your horse’s natural oils swirling around. Inspect every last inch of your horse in the process.


  • Notice if your horse has rumpled hair from rubbing himself.


  • Does he seem extra itchy as you are grooming?


  • Is he shedding naturally, or are there clumps of hair falling out?


  • Does any part of your horse’s skin seem oilier, drier, scalier, or just different from the rest of his skin?


  • Is he rubbing his mane or tail? Or both?


  • How is the overall quality of his hair? Any changes or anything new?



The rest of skincare is just management.



  • Remove blankets and fly sheets daily. This keeps you ahead of rubs and sores.


  • Keep your horse’s bedding clean. Regular cleaning also helps with fly control.


  • Clip your horse for his health, not for his looks. Sometimes, having a horse sweat in a winter coat creates infinitely more problems than not clipping him.


  • Clipping certain affected areas help a problem area remain clean and dry. Topical treatments and medications will reach their destination more effectively, too!


  • Work with your vet to narrow down possible causes of any skin irritations you find. Early intervention saves you money and helps your horse heal much faster!


Rain rot, part 1

Rain rot part 2



Sweet itch


Girth galls

Aural plaques in horse ears

How to use Sox for Horses



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