Crusts in the pastern. Reddened skin. Small oozing patches. And it's been raining outside for days. Many horse owners are familiar with this picture, especially in the wet season, and simply call it: mud fever.
But mud fever is more complex than the name suggests. It is not a single disease with one single cause. And it does not occur automatically just because a horse is standing in mud.
That is precisely why we want to take a closer look.
What actually is mud fever? Why do some horses keep getting it? Should you remove the crusts? Are you allowed to wash mud fever? What helps with oozing mud fever? And when does the vet need to come?
And, of course, at STEINKRAFT we are particularly interested in one more question:
What can natural zeolite do for mud fever?
For many years, we have been working with clinoptilolite in horses – in feed, on the skin, on the hoof, and in the bedding. And especially when moisture, irritated skin, and a burdened skin environment coincide, this extraordinary natural mineral becomes interesting.
Equine Pastern Dermatitis (Mud Fever) – in a nutshell
- Mud fever is an inflammation of the skin in the pastern area.
- In veterinary medicine, it is referred to as Equine Pastern Dermatitis (EPD).
- Mud fever is not a single disease, but a syndrome with various possible causes.
- Moisture and mud can promote its development or persistence.
- Mites, mechanical irritation, secondary bacterial infections, skin barrier disorders, and individual predisposition can also play a role.
- Therefore, there is no single mud fever treatment for every horse.
- Firmly attached crusts should not be torn off forcefully.
- Constant washing can further irritate skin that is already compromised.
- For superficial, moist, or oozing skin areas, finely ground clinoptilolite is particularly interesting to us due to its adsorptive properties.
- For dry, irritated, or healing skin areas, a nourishing zeolite ointment may be the more suitable variant.
- Dry pasterns and a dry, clean environment go hand in hand.
- In cases of severe inflammation, swelling, pain, pus, lameness, or recurrent mud fever, the cause should be clarified by a veterinarian.
What actually is mud fever in horses?
Is mud fever a disease?
That is the very first important question.
Strictly speaking, mud fever is not a single disease.
In veterinary medicine, it is usually referred to as Equine Pastern Dermatitis (EPD).
Veterinary dermatologist Anthony Yu describes EPD as a cutaneous reaction pattern or syndrome, rather than a single diagnosis. This is more than just medical hair-splitting.
Because it explains why two horses with seemingly the same “mud fever” can react completely differently to the same treatment. We may see crusts, redness, and oozing skin on the outside.
What we don't know yet is:
Why is this horse's skin diseased?
That is exactly why, for us, good mud fever treatment always includes the search for the contributing or underlying factors.
How to identify mud fever in horses?
What does mud fever look like at the beginning?
At the beginning, the changes are sometimes surprisingly subtle.
Perhaps the skin in the pastern suddenly feels rougher. Small scales form. The hair becomes a little matted. The skin is reddened or more sensitive.
Later, the following can be added:
- Crusts
- oozing skin areas
- cracks
- swelling
- heat
- itching
- pain
- thickened skin
- matted hair.
Some horses suddenly pull their leg away when you touch the pastern.
That is exactly why we like a very simple ritual in autumn:
Don't just look. Feel.
Run your hand down each leg and deliberately feel the pastern area. The earlier we notice changes, the earlier we can react.
Why does a horse get mud fever?
What are the most common causes of mud fever?
This is where one of the biggest misconceptions lies:
Mud fever does not have one single cause.
Veterinary literature describes an interplay of primary causes, predisposing factors, and factors that can further maintain an already existing inflammation.
These include, among others:
- Moisture and mud: Constant wetness can soften the skin and burden its natural barrier.
- Mechanical irritation: Sand, dirt, friction, and small injuries can put additional strain on the skin.
- Parasites: Especially in horses with heavy feathering, mites must also be considered.
- Microorganisms: If the skin barrier is already damaged, bacteria can become part of the problem.
- Other skin diseases: Not every crusted pastern has the same cause.
- Individual predisposition: Pigmentation, feathering, breed, and other individual factors can play a role.
The first question should therefore not just be:
“What should I put on the mud fever?”
But also:
“Why does this particular horse have this skin change?”
Mud fever in autumn: What role do mud and moisture play?
Does mud fever come from mud?
Not automatically. But the connection between mud fever and moisture is very relevant for management.
A prospective scientific study followed young horses from August to October and regularly examined their pastern areas. Moisture was identified as a predisposing factor; unpigmented pastern areas were also affected more frequently.
Other overview studies show, however, that the link between precipitation or humidity and EPD is not equally clear in all studies.
This is typical for a multifactorial event: Mud alone does not make mud fever.
But constantly moist, softened, and soiled skin is a factor that we can influence, especially in a sensitive or already damaged horse.
In autumn, several things also come together:
Rain.
Mud.
Wet hair.
Moist pasterns.
More time in the stable.
And sometimes wet bedding afterwards.
In our guide “Horses in autumn – natural support during weather changes and mud” you will find further tips on the special challenges of the wet season.
Why do some horses keep getting mud fever?
Are white legs more susceptible to mud fever?
There is scientific evidence for this. In the prospective study, unpigmented pastern areas were affected more frequently than pigmented ones.
This, of course, does not mean that every horse with white legs gets mud fever.
But it is a good reason to observe these skin areas with particular attention in a horse that is already affected repeatedly.
Are horses with lots of feathering more susceptible?
We also see mud fever more frequently in horses with heavy feathering. Under thick feathering, moisture can remain on the skin for longer. At the same time, for example, mites can be overlooked more easily.
Therefore, especially with Tinkers, draft horses, and other horses with distinct pastern feathering:
Do not just look from the outside. Go down to the skin with your fingers.
Why does the mud fever keep coming back despite treatment?
That is when we would become particularly attentive. Because perhaps we keep treating the visible skin change, while the triggering or maintaining factor remains.
- What does the keeping environment look like?
- Does the horse stand in constant moisture?
- Are mites involved?
- Is it always the same pastern affected?
- Is there severe itching?
- Are only white legs affected?
- What does the skin barrier look like?
Recurrent mud fever is therefore a good reason to look for the cause together with your veterinarian – instead of just trying the next jar of ointment.
Is mud fever a bacterial infection?
Are bacteria the cause of mud fever?
Not automatically. In cases of more severely changed skin, certain bacteria are indeed detected more frequently. But:
Finding a bacterium on inflamed skin does not automatically mean that this bacterium was the original cause.
The skin barrier may have been damaged initially for another reason. Microorganisms can subsequently become part of the problem.
This is also interesting for zeolite – we will come to that in a moment.
What really helps against mud fever in horses?
How do I get rid of mud fever in horses?
Unfortunately, there is no universal three-step guide for this.
Because mud fever can have different causes, the treatment must also fit the horse and the condition of its skin.
Veterinary literature emphasizes two levels here:
treating the specific skin change
and
changing predisposing or maintaining factors.
For us, this means in practice:
- Examine the skin.
- Search for the cause.
- Manage moisture.
- Check the environment.
- Choose suitable skincare.
- And have it diagnosed in case of more severe changes.
Should you wash mud fever?
Do I have to wash the pastern daily?
More is not automatically better here. Of course, a heavily soiled pastern may need to be cleaned.
But again and again:
washing – soaping – disinfecting – rinsing – making it wet again
can also be counterproductive for an already compromised skin barrier.
If you do wash it, you should dry it thoroughly and gently afterwards.
Especially with moist or oozing mud fever, we find the thought interesting not to always add even more liquid to the skin, but to get the skin environment drier.
And this is exactly where we come to zeolite.
Zeolite for mud fever – why we find the natural mineral exciting precisely here
Anyone who has known STEINKRAFT for a while knows: For us, zeolite for horses is far more than just a mineral for feed.
We have been working for many years on what high-quality clinoptilolite can do in the horse, on the horse, and in its environment.
And with mud fever, several things come together where its physical properties become interesting:
Moisture – wound exudate – irritated skin – microorganisms – burdened skin environment.
Clinoptilolite has a microporous crystalline structure and a large internal surface area.
Simply put:
There is an incredible amount of surface area in an incredibly small space.
Liquids and various molecules can be adsorbed there.
Exactly these properties are also the subject of modern skin and wound research.
Those who would like to delve deeper will find the individual studies and backgrounds explained in detail in our major research article “Zeolite for the skin: What studies on the effect really show”.
What does research say about zeolite on injured skin?
Is clinoptilolite even allowed to come into direct contact with a wound?
There is now clinical research on this. In a prospective randomized phase I study by Deinsberger et al., purified clinoptilolite tuff in powder form was applied directly to standardized open skin wounds of healthy volunteers.
This is remarkable to us:
- The mineral was not just studied theoretically in the laboratory.
- It was applied directly to injured skin.
- The application proved to be well tolerated. The researchers found no significant differences in macroscopic wound healing compared to standard care.
- Histologically, however, differences were shown in the wound tissue – including more macrophages and fewer myofibroblasts in the wounds treated with clinoptilolite.
- Occasionally, small zeolite particles were found in the newly formed skin tissue, without these being associated with clinical symptoms or an impairment of wound healing.
For us, therefore, the correct conclusion is not:
“Zeolite cures mud fever.”
But rather:
Purified clinoptilolite has been clinically studied directly on open skin wounds, was well tolerated there, and is scientifically interesting for wound management due to its special material properties.
What can zeolite do for moist and oozing skin areas?
Can zeolite absorb wound exudate?
That is precisely one of the properties being investigated in zeolite wound research. Finely ground clinoptilolite can absorb liquid or wound exudate onto its large surface area.
For us, this is particularly interesting in the case of mud fever. After all, we do not want to keep a damp, weeping pastern in a warm, moist microclimate for long.
Our reasoning is therefore:
Absorb moisture – keep the skin environment drier – observe.
What is known about zeolite for chronic wounds?
In addition to controlled studies, there are also clinical observations.
In the observation by Becher et al., which we have already reviewed in our skin research article, tribomechanically treated clinoptilolite was used as a powder on 33 patients with acute or chronic wounds, some of which were difficult to heal.
Among other things, the drying out of heavily secreting wounds and changes to the wound environment and microbial load were described.
An observational study is not proof of efficacy specifically for mud fever.
But together with the clinical safety study and experimental data, it shows very nicely why clinoptilolite is interesting precisely in a moist wound environment.
What does research say about zeolite for inflamed skin?
Is there research on zeolite for dermatitis?
Yes – and this research is also interesting for our mud fever question, even though it was not conducted directly on horses.
In our STEINKRAFT skin research article, for example, we reviewed an experimental study on atopic dermatitis.
In a mouse model, clinoptilolite powder was applied directly to inflamed skin and compared with tacrolimus.
Both clinical skin scores and histological changes improved compared to the untreated dermatitis group; there were no significant differences between the zeolite and tacrolimus groups for several parameters.
This is not a mud fever study.
But it expands our understanding that clinoptilolite is not only being scientifically investigated as a "dry powder," but now also in inflammatory skin models.
Zeolite for mud fever: powder or ointment?
When would we use zeolite powder?
For superficial, damp, or weeping skin areas, we find finely ground zeolite powder particularly interesting due to its adsorptive properties.
The idea behind it is simple:
Absorb moisture and support a drier skin environment.
Here we use our finely ground TIERKRAFT Zeolite Skin Powder.
When is a zeolite wound ointment more appropriate?
A dry, cracked, or already healing skin area has different needs than a heavily weeping pastern.
Here, a nourishing ointment base can be more appropriate.
Our Zeolite Wound Ointment for Horses & Dogs combines finely ground clinoptilolite with an ointment base and has been used by our customers for years on minor injuries, irritated skin areas, scars, and also for mud fever.
Our simple guideline is therefore:
weeping/damp → preferably powder
dry/cracked/needs care → preferably ointment
And of course, the following always applies: Don't just choose the product. Look at the skin.
What do our customers experience with zeolite for mud fever?
Is there experience with zeolite for mud fever?
Yes. And one of them comes directly from a stud farm.
From STEINKRAFT practice
“The wound on the head healed faster thanks to the zeolite ointment! We also use it successfully for mud fever and scratches.”
Tasdorf Stud Farm
That is a customer experience, not a clinical mud fever study.
But that is exactly why we show it:
We want to distinguish between what has been scientifically investigated and what horse owners observe in practice.
Both are valuable to us – as long as we do not confuse them with each other.
Further experiences with zeolite for horses can be found on our page “Zeolite Horse Experiences – what horse owners report”.
What do mites have to do with mud fever?
Can mites cause mud fever?
Mites can play a role, especially in horses with heavy feathering, and should be considered as a possible cause in the case of recurring skin problems in the pastern area.
This is interesting because we also receive feedback on the use of our skin powder from this area.
A horse owner reported to us about using zeolite skin powder for mites in the pastern area and observed a clear improvement in the skin within a few days.
Important:
Mites in the pastern area are not automatically the same thing as mud fever.
But the experience shows very nicely why it is worth not just saying "mud fever" when dealing with pastern problems, but looking more closely.
Should you remove crusts in cases of mud fever?
Am I allowed to scrape off mud fever crusts?
We would not simply rip off firmly attached crusts when dry.
Anyone who removes them forcefully can re-injure the underlying skin, cause pain, and create new small wounds.
Depending on the findings, careful softening and removal of already loosened material can be part of a treatment.
But there is a big difference between “carefully loosening” and “scraping everything off.”
What role does the environment play in mud fever?
Does the stall need to be particularly dry for mud fever?
Here we come to a point that is almost as important to us at STEINKRAFT as skin care.
After all, what is the use of a carefully tended pastern if the horse then stands on wet bedding for hours?
That is why we think of mud fever from the top and from the bottom.
Top: keep the skin dry and clean.
Bottom: observe the ground and the bedding area.
Especially in autumn, the bedding can be more heavily burdened by more time in the stall, wet hooves, and urine.
We explain in detail how moisture, ammonia, and natural zeolite interact in our guide “Horse stall in autumn: Moisture & ammonia – how to keep the stall climate pleasant.”
Why is zeolite bedding interesting for mud fever?
What does HORSEKRAFT bedding have to do with a skin disease?
It does not treat the mud fever. But it helps us manage an influenceable environmental factor: moisture in the stall.
Our HORSEKRAFT bedding with natural zeolite is used as a supplement to normal bedding, particularly where moisture and urine occur.
Clinoptilolite not only possesses adsorptive properties but can also bind ammonium via ion exchange.
This results in a very logical mud fever strategy for us:
- Keep the skin dry.
- Observe the pastern.
- Manage mud.
- Keep the stall dry.
Anyone who wants to know more about this use will find the background information on clinoptilolite, bedding, and ammonium binding in our specialist article “Zeolite bedding – binding ammonia and keeping the horse stall dry.”
Mud fever and thrush – are they connected?
Can a horse get mud fever and thrush at the same time?
Of course – because they are two different problems.
Mud fever affects the skin of the pastern.
Thrush affects the hoof or the frog.
But both have an important interface:
Moisture and unfavorable environmental conditions.
That is why, with a horse that has mud fever in the wet autumn, we automatically look one level lower as well.
- Pick out hooves.
- Check the frog clefts.
- Smell.
- Watch out for black, greasy areas.
And the reverse is also true. If a horse is being treated for thrush, a look at its pasterns is also worthwhile.
In our detailed guide “Thrush in horses – causes, symptoms, treatment & prevention,” we explain this topic in detail.
And anyone who wants to see how zeolite hoof powder is used in practice can find our field report with multiple Olympic champion Heike Kemmer, who uses our zeolite hoof powder in her stable.
Our STEINKRAFT approach to mud fever: top AND bottom
When we put it all together, it doesn't result in a complicated therapy formula.
But rather a very natural look at the horse.
1. Look at the skin
Dry? Wet? Crusty? Warm? Swollen? Painful?
2. Consider the cause
Mud? Moisture? Mites? Skin barrier? Recurring problem?
3. Support the skin environment appropriately
For superficially weeping areas, finely ground zeolite can be interesting due to its adsorptive properties.
For dry, cracked, or healing skin, a zeolite ointment may be a better fit.
4. Check the environment
Mud outside and damp bedding inside should be taken into account.
5. Recognize limits
Severe inflammation should be diagnosed and treated in a targeted manner.
This is zeolite competence to us:
Not just putting powder on everything. But understanding which property of the mineral we want to use at which point.
When should you call the vet for mud fever?
When should I stop treating mud fever myself?
Please do not experiment for weeks with various home remedies if the condition worsens.
In particular, we would have the following clarified by a vet:
- significant swelling
- intense heat
- pain
- lameness
- heavily weeping or suppurating areas
- rapid spread
- severe itching
- suspicion of mites
- heavy skin thickening
- repeatedly recurring mud fever
- no improvement despite sensible care.
Because mud fever initially describes what we see. Not automatically why it originated.
Can you prevent mud fever?
What can I do in autumn so that mud fever does not develop in the first place?
Not every case of mud fever can be prevented. But we can do a lot to ensure that the skin and environment are not unnecessarily burdened.
- Observe muddy areas.
- Avoid permanently damp pasterns.
- Remove wet bedding.
- Ensure dry lying surfaces.
- Check pasterns regularly by hand.
- Look particularly closely at horses with heavy feathering.
- Pick out hooves and check the pastern at the same time.
- Notice small skin changes early.
- And do not constantly treat healthy skin prophylactically with aggressive agents. Because an intact skin barrier is itself an amazingly good protection.
Our little autumn ritual: running your hand down once
When you bring your horse in from the paddock in autumn, consciously run your hand down each leg once. Over the cannon bone. To the fetlock. And into the pastern.
Is it dry? Warm? Swollen? Does the skin feel smooth? Or rough? Are there small crusts? Does your horse suddenly pull its leg away?
Then pick out the hooves.
And later, when mucking out, take a look at how dry the favorite lying spot actually is.
That takes maybe three minutes. But we begin to perceive changes before they become big.
And we like that much better than any miracle cure.
Frequently asked questions about mud fever and zeolite
❓What really helps against mud fever in horses?
That depends on the cause and severity. Mud fever is a syndrome and not a single disease. Therefore, appropriate skin care, clarification of the cause, and the optimization of moisture and management belong together.
❓Does mud fever come from mud?
Mud alone does not automatically cause mud fever. Permanent moisture can, however, burden the skin barrier and is one of the environmental factors that should be considered, especially in susceptible horses.
❓Should one keep mud fever dry?
A permanently moist skin environment should be avoided as much as possible. At the same time, the right local treatment depends on the respective skin condition. Severely inflamed or weeping changes should be professionally assessed.
❓Should one wash mud fever?
In the case of dirt, gentle cleaning may be necessary. Frequent washing and insufficient drying can, however, additionally burden an already disturbed skin barrier.
❓Should one remove mud fever crusts?
Firmly attached crusts should not be forcefully torn off. Depending on the finding, careful softening and removal of loosened crusts can be sensible.
❓Which ointment helps with mud fever?
There is no universally best mud fever ointment. What is decisive is, among other things, whether the skin is dry, cracked, weeping, inflamed, or secondarily infected. At STEINKRAFT, we use our zeolite wound ointment especially for the care of dry or healing skin areas.
❓Does zeolite help with mud fever?
Clinoptilolite possesses strongly adsorptive properties and is particularly interesting where moisture and a burdened skin environment meet. Zeolite is being scientifically investigated in skin and wound management. A clinical study showed that purified clinoptilolite was well tolerated directly on open skin wounds. There is currently no clinical proof of efficacy specifically for mud fever in horses.
However, from our practice and from customers, we have had good experiences with the external application of zeolite for skin problems and specifically for mud fever.
❓Can I apply zeolite powder to weeping mud fever?
For superficial, damp, or weeping skin areas, we find finely ground clinoptilolite particularly interesting due to its ability to adsorb moisture or exudate.
For deep, heavily inflamed, suppurating, or painful changes, one should first clarify what cause lies behind it.
❓Zeolite powder or zeolite ointment for mud fever?
As a practical guide, we use powder more where moisture needs to be absorbed. An ointment fits better for dry, cracked, or skin in need of care.
The actual condition of the skin always remains the decisive factor.
❓Why does mud fever keep coming back?
In such cases, predisposing or sustaining factors may persist. Moisture, mites, skin barrier disorders, mechanical irritation, and individual predisposition are some possible factors. Recurrent mud fever should be evaluated by a veterinarian.
❓Are white legs more prone to mud fever?
There is scientific evidence for this. In a prospective study, unpigmented pastern areas were more frequently affected by pastern dermatitis than pigmented areas.
❓Are horses with feathers more prone to it?
Horses with heavy feathering on their lower legs are presented more frequently with mud fever or pastern dermatitis. Furthermore, skin changes under dense feathering can be overlooked more easily; mites should also be considered if the corresponding symptoms are present.
❓Is mud fever contagious?
As a syndrome, mud fever itself is not generally contagious. However, depending on the underlying cause, factors such as parasites or infectious agents may be involved.
❓Can zeolite bedding help with mud fever?
HORSEKRAFT bedding does not treat mud fever. However, it can assist in the management of an important environmental factor: keeping the lying area as dry as possible. The natural clinoptilolite it contains supports moisture management and binds ammonium through ion exchange.
❓When should I take my horse to the vet for mud fever?
In cases of significant swelling, heat, pain, lameness, pus, severely weeping areas, rapid deterioration, intense itching, or recurrent mud fever, the cause should be clarified by a veterinarian.
Conclusion: With mud fever, don't just look at the scab
Autumn brings rain. And rain brings mud. But mud alone doesn't explain mud fever. Mud fever is a complex skin problem where various causes and environmental factors can interact.
That's why we particularly like this thought: Don't just treat what we see. Understand why it developed.
Look at the skin. Observe the horse. Manage moisture. Keep the stable dry. Check the hooves as well. And for severe or recurring problems, have the cause investigated.
For us, natural clinoptilolite zeolite is far more than just a "home remedy".
Its porous structure, large surface area, and adsorption properties make it a fascinating natural material, especially where moisture and a compromised skin environment meet.
That is why we use it for horses on several levels:
as a powder on the skin – as a zeolite wound ointment for care – and as a component of our bedding under the horse.
Above and below. Skin and environment. Because perhaps good horse care begins exactly there: not waiting to react when something has become a major issue – but noticing what is changing early on.
Science & further knowledge
Yu, A. A. (2013): Equine Pastern Dermatitis. Veterinary Clinics of North America: Equine Practice, 29(3), 577–588.
Basic veterinary overview of equine pastern dermatitis as a syndrome, as well as its causes, diagnostics, and treatment.
Gerber, V., Kaiser-Thom, S. & Oesch, S. (2023): Equine pastern dermatitis: A narrative review.
A more current scientific classification of the complex causes and risk factors of pastern dermatitis.
Deinsberger et al. (2022): Topically administered purified clinoptilolite-tuff for the treatment of cutaneous wounds: A prospective, randomised phase I clinical trial.
Clinical examination of purified clinoptilolite applied directly to standardized skin wounds. Good tolerance and interesting histological differences; no significant difference in macroscopic wound healing compared to standard care.
Becher et al. (2019): Clinical observations on the use of tribomechanically treated clinoptilolite for acute and chronic wounds.
Observational data from practical wound care, which are of interest for heavily secreting or compromised wound environments, among other things.
Further research on zeolite & skin
We have compiled studies on clinoptilolite for inflammatory skin, wound exudate, adsorption, and other dermatological applications in detail in our STEINKRAFT research article "Zeolite for the skin: What studies really show about its efficacy".
Read more:
→ End of the grazing season in autumn - gently transitioning feeding from grass to hay
→ Treating fecal water in horses naturally – causes, home remedies & zeolite tips
