Scabbed, Scalded and Sore – Wet Weather and Your Horse’s Skin

It’s not much fun being hit by a years’ worth (or more) of rainfall in a few days, as dwellers on Australia’s east coast are yet again experiencing.

In the aftermath of the storms, we often witness a problem common to horses caught in the big summer deluges of the tropics and sub-tropics.

Please note: if your horses has been trapped in deep water, as has happened in some areas of NSW in 2021, your local veterinarian or emergency veterinary services are your first port of call. This post is very much aimed at horse owners in non-emergency situations with non-traumatised horses.

It was originally published after ex-Tropical Cyclone Oswald hammered the South East Queensland and New South Wales coast for several days in January 2013.

 

The Cause: Mud Fever, aka Greasy Heel

There’s no doubt about it, Aussie owners aren’t as familiar with mud fever as owners in countries that are far more – well – muddier. Hailing from England, I know about it only too well. Yet in this wide brown dry land, where it also goes under its local name of greasy heel, it’s far less common.

Or at least, it was less common. I’m seeing a lot more in 2021 2025 than I did in 2013.

The cause of the swelling and crusting skin we see with mud fever is a reaction to the early stages of bacterial or fungal infection.

Put simply, during the periods of unrelenting rain, the skin becomes softened and the many microscopic scratches around the pasterns and lower legs are exposed (imagine tiny scabs going soft).

The ‘bugs’, which thrive in damp conditions, enter these tiny scratches and abrasions. As the horse’s body starts to fight the invaders off, the swelling occurs.

Not all horses will develop the problem further, as it depends on how strong their immune systems are. Some will fight it off. But while there’s visible swelling, possibly accompanied by redness on white legs, sometimes with crusting skin and the beginnings of scabs, the horse’s body is in defense mode.

The problem usually affects the hind legs more than the front, but as it progresses, all four legs can be affected.

 

Partner in Crime: Rain Scald

Rainscald, also known as rain rot, is caused by the same bacterial agents and is also a form of dermatitis. The bacteria cluster in the damp, warm zone at the base of the hair, next to the skin.

You don’t see the signs as quickly as with greasy heel, but you may notice your horse has increased sensitivity along the centre line of the back – especially if they are rather overweight and have a ‘rain channel’ down the middle.

 

Where Does Greasy Heel Come From?

Both rainscald and greasy heel/mud fever are caused by an invading dermatophilus or staphylococcus. Greasy heel may also be caused by fungal infections such as dermatophytes.

The microbes that cause rainscald are often already living on the skin of horses, without causing any problems. However, during a period of heavy rainfall, especially in our warm regional climate, they become more active and release ‘zoospores’.

They get happy: they breed.

The spores infect the skin where it’s weaker, with the discharge then clogging into the familiar paintbrush tufts of hair and scabs after a few days.

It’s entirely possible that some paddocks present horses with the greasy heel and rainscald bugs more than others. I’ve certainly had horses that were fine until they changed properties and then suddenly seemed to ‘pick something up’.

 

Why Is This Such a Problem After Storms?

Good question. It’s not as if we don’t regularly get 2 or 3-day episodes of non-stop rain. The high incidence of swollen legs relating to mud fever may be due to several things. Shall we speculate?

Was the weather extremely hot before and after, and maybe during the event? The conditions may have been particularly favorable to the bacterial activity.

If there’s rain and also high winds, it’s likely that horses stopped moving around as much.

Lack of movement leads to poor circulation, which leads to fluid build-up anyway, as well as reduced resistance to nasty little pathogens.

But in truth, I don’t know for sure. I’d be interested to hear other ideas. (There’s a comments section at the end.)

Whatever the reasons, I still feel it’s best to come down hard on problems like mud fever or rainscald, as they’ll only come back another time, making your horse uncomfortable and setting you to work on it all over again.

 

Are These Skin Problems Serious?

These infections can be surprisingly painful for the horse. If your horse has greasy heel and scabs form, and your property is still flooded or at the least muddy, then you need to act quickly if it’s not to become a more serious problem.

The horse needs to flex at the fetlocks whenever it moves, so if the scabs remain on the pasterns, they will crack repeatedly and the lesions beneath will grow larger.

(This is why the condition is also known as cracked heel.) Your horse may well become lame.

Rainscald is painful for the horse even before the ‘paintbrush tufts’ appear. It will remain so until the scabs have all come away and the skin beneath has healed.

Horses severely affected by rainscald may develop a fever, become depressed, lose their appetite and become lethargic.

They may also have swollen lymph nodes… these are all signs of a body defending itself against pathogens.

 

How to Treat the Bacteria

Once you realize you’re looking at infection, it becomes more apparent that something needs to be done. There are many suggested remedies you can try once the reaction has started – here are a few.

The initial swelling should subside with movement and exercise, as the lymph fluid is shifted away.

If the horse has developed scabs, you can soften and remove these before applying treatments.

I’ve previously used aqueous cream for small scabs, which soaks and lubricates them, so that they then slide off gently. I’ve also seen paraffin oil or olive oil suggested. If the scabs are covering much larger lesions, you may need to progress more slowly, over several days, as removal will be painful for the horse.

Here are some treatments you can try, recommended by different people in the equine industry.

1. A diluted iodine solution can be used on the legs, to zap the bacteria.
2. For greasy heel and rainscald, an anti-microbial shampoo is another option for scab removal – Maloseb, normally used for cats and dogs, is gentle and contains chlorhexidine gluconate (2% content).
3. For rainscald, you can ease off the scabbing at an early stage, either with an oil-based product, or even with olive oil, before rinsing the back with iodine. Use it well-diluted or it may sting.
4. Products used by vets and medical staff containing chlorhexidine gluconate offer a gentle antibacterial action. Microshield is a good product (5% content) that can be diluted and used on horses’ legs and backs. You can buy it online or from Chemists Warehouse in Australia.
5. A poulticing product such as Tuffrock can be applied to the affected areas. This has some antibacterial properties – if scabbing is present, it’s better to also use an antibacterial agent.
6. The herbal approach is to use coconut oil on the lower legs. You could also try using this before the rains come, providing  you have advance warning, so that a protective layer is built up. This can help prevent bacteria from entering the skin.

 

Make Greasy Heel Go for Good

If infection is present, you may need to work on the area for a few days running to ensure that the bacteria are well and truly zapped. You want to reduce the chances of it recurring – ridding your horse’s skin of the bacteria is definitely one way to do that.

That’s not to say it’ll never happen again, but as ever, prevention is better than cure.

One of the most helpful things we can do for our horses is to work on their underlying condition, boosting their immunity through use of probiotics to improve gut function, while providing adequate nutrition and mineral supplementation.

And – well, I would say this – bodywork will ensure the upper layers of tissue, including the skin, are nourished and functioning as they should, while circulation is good.

Extreme weather is never easy to deal with, but with a bit of organization, we can ensure our horses come safely through it without experiencing an unnecessary degree of discomfort and even pain.