Treating Mud Fever – Rain Rot – Mud Scald – Rain Scald

Out of the main things that can go wrong with a horse, mud fever, is definitely one that can go undetected and out of hand quickly. Mud fever,  has many names like mud scald, rain scald, rain rot and most precisely, pastern dermatitis. Essentially, it’s a skin issue. Rehab only comes into play if it becomes very serious, more on that below.

This issue primarily affects the pastern area of the horse but can also go up the leg, under the belly and can also affect the back and neck area. Leaving blankets on horses is a big one when it’s rainy and wet outside and the water seeps under and stays, to cause this skin issue, but it happens without as well. Horses with more sensitive skin, poor diet and general age issues will be more prone to this and need to have it managed. Some of the diet based ways of proactively dealing with this is to make sure your horse gets enough essential oils in it’s diet. Flax seed, washed COB (the stuff in the bag is coated in molasses, no good for a horse so it’s best to rinse it off) and other seed based oils are good. Some people use vegetable oil straight in the grain or mash that is provided daily.

So back to what it looks like and what it is. Here’s a larger picture of it:

[responsive]Mud Fever Example[/responsive]

This would be considered a serious case and must be dealt with immediately and aggressively. This horse presented with a slight limp, inflamed, swollen and very warm pasterns which was steadily traveling up the leg. The horse wouldn’t lift the opposite back foot without trouble and it was clear that it was hurting. In other cases it may just be something as minor as a few scabs here and there, small patches the size of a dime are common. Managing those are simple and pretty much the same as this one, but less critical as it’s likely the foot and leg will not be sore, inflamed or swollen.

Mud fever is something that once it takes hold, almost always requires human intervention to rid the horse of it. It thrives in moist and wet conditions and can take right over in the right conditions like poor pasture and paddock maintenance. It’s not as likely to happen in the summer time when it’s dry, but it can, especially if it has already been there over the wet spring season and muddy winters. Something small can take less than a month to reach the stage that we see in the above picture.

Dealing with this problem is almost the same no matter the amount that there is. In this case if we were to just simply take the scabs off, the horse would bleed. We don’t want that.

Here is an example of something smaller

[responsive]Small infection of mud fever on pastern[/responsive]

For smaller infections that are more surface level, carefully picking off the scabs is the accepted treatment. You can see in the picture above that it must have been a bit of effort (it was) as it looks like an open wound now. It’s preferable to not have to get so far, but sometimes it’s required.

From there you can apply zinx oxide (yes, diaper cream) to help keep moisture out and likely you will see it all disappear within a week. The deal here is that the moisture and dirt is thriving as it just stays stuck in there. The scabs don’t help and in fact if you have hairy horses, they would do well to be shaved (very carefully) to get rid of the ability to retain moisture there. Keep in mind that for mares, if they can’t get their feet far enough apart or live on footing that causes lots of splash then the moisture comes from their urine. In such a case, being summer time is irrelevant.


As mentioned above, when we have smaller bits of this particular skin infection, the scabs will be easy to pick off with your fingers. In many cases it’s a great idea to rinse it down and soften them up before picking them off. Once that is done, rinse again, clear it as best as you possibly can. If you can dry it with a paper towel or something, do so. Keep in mind that this is bacteria and should be treated as an infectious skin disease. In other words, wash your hands when you’re done and don’t touch other horses while you’re doing this nor use tools that you have used on the infected horse. Kind of like thrush, don’t use the same hoof pick on many horses if you suspect or know of thrush. You’ll just give it to all of them.

So, once you have those scabs cleanly picked off, keeping in mind that it will likely bother or hurt your horse, don’t get kicked or bit, you can then give it a last wash with clean water, dry if possible and apply treatment.

Here is what it should look like after treatment, don’t mind the strands of tail in the foreground.

[responsive]Mud fever on pastern treated with zinc oxide powder[/responsive]

Here’s the important point on treatment: While we usually apply zinx oxide, it will depend on the condition of the area we are applying it to. If you have the option to do the cleaning with water, it won’t matter how much you dab with a paper towel, you will still have moisture there. That’s ok. You can certainly wait half an hour or so but if it’s a mare and she pees… well, then you’re back to washing it and another half an hour. My recommendation is just to get some athlete’s foot powder. It’s primarily zinx oxide. Get the good stuff, not the cheap stuff though. Put as much as you can on the affected spot and rub it in. If there is moisture then this powder will suck it right up and then it turns into cream that resists any further outside moisture. Like two birds with one stone here.

In the case that the foot is dry and you didn’t have the opportunity or ability to wash it, then just apply the diaper cream. Again, the expensive stuff is better as it has a higher amount of zinx oxide in it, in a pinch the cheaper stuff does work. Keep an eye on it over the next week, apply a bit of zinc oxide each day, don’t do any cleaning. If you can get your horse out of whatever wet or moist or unclean conditions as you can, do so obviously. If not, apply zinc oxide liberally to the area, it’ll help. In a week or so you should see small infections go away, unless your horse is unhealthy, then it may take longer to recover.

For cases that are more serious, like the first picture above, it will take more time and the procedure is slightly different. This article here talks about it in more detail. First thing is that in under no conditions should you pick off scabs that look like they will bleed. For example, the horse in the picture’s middle of the pastern is a no-go area. Don’t touch it at all, way too tender and fragile. In this case, the scab is a requirement, we’ll cover it all the same though with zinc oxide. In the horse above we would pick away at the edges as much as possible. Do not let this get out any further. As you clear up the skin around the central location of it, the skin will get stronger. Also, as you are applying the zinc oxide (as noted above), the middle area will slowly start to dry out and heal from the inside out. It will just be a matter of time before you can get all that scab off safely.

In the case you cause bleeding, apply a good anti bacterial cream like polysporin first, then athletes foot powder. Do not use the zinc oxide cream in this case as you’ll just mix it up and the anti bacterial cream won’t work as well. The powder will sit on top nicely and protect it from getting washed off. In the horse above, this was done for the middle area without even taking the scabs off. Any cream you can put on there that will help the skin heal will help the horse fight off the bacteria. Covering that cream with the powder keeps it on longer, don’t wrap it.

With the above method, the horse above looks like this less than 2 weeks later:

[responsive]Mud fever infection in pastern cleaned up and ready for treatment[/responsive]

Keep on top of this daily. You won’t be picking off scabs everyday but maybe every few days. Each and every time you pick of a scab, cover it with powder or cream. Once the scabs stop forming then you can lay off and let the horse take over. While I have seen articles to say that you should wrap it, I believe there is absolutely no case that should be wrapped unless it’s bleeding profusely. This infection needs to dry out and die and it can’t do that if it’s wrapped up. If it’s raining, don’t worry, rain doesn’t get under zinc oxide. Again, be liberal with your application, use lots.

Mud fever is a manageable affliction and just requires perseverance and care. Keep the conditions of the horse clean and dry and it shouldn’t really happen, again though if you’ve got a mare that urinates on the back of her feet (very common) then it can happen no matter what. Don’t worry, just manage it with the steps above and all should work out well.