Understanding Mud Fever in Horses

Understanding Mud Fever in Horses

A Common Winter Woe: It’s a dreary winter morning; you bring your horse in from the paddock and notice scabs on his hind legs. This scenario is all too familiar to many horse owners. Mud fever (also known as pastern dermatitis or “greasy heel”) is a common skin infection in wet weather that can cause pain and discomfort. The good news is that with some knowledge and consistent care, you can prevent mud fever and manage it effectively when it does occur. This article explains what mud fever is, why it happens, how to prevent and treat it, and when to seek help – so you can keep your horse healthy and comfortable.

What is Mud Fever?

Mud fever is a non-contagious skin condition that causes irritation, scabby sores, and inflammation on a horse’s lower legs. In other words, your horse can’t “catch” mud fever from other horses – the problem starts with bacteria infecting the skin. Mud fever typically appears as clusters of crusty scabs with raw, oozing skin underneath, usually around the pasterns (just above the hooves) and the heels. Affected areas may be swollen, warm, and painful to touch. You might see discharge (a creamy white, yellow, or green pus) under the scabs and notice patches of hair loss. In mild cases, a horse may not be very lame, but severe mud fever can cause significant pain or even lameness. Some horses have just a small patch of scabby skin; others can develop sores that spread up the legs or even to the belly in extreme cases. Every horse is a bit different – some seem hardly bothered, while others get very sore. But all cases of mud fever need prompt attention to prevent complications.

Why Does It Happen?

Mud fever is typically caused by bacterial invasion of compromised skin, but it's now recognised as a multifactorial condition involving multiple types of bacteria, not just a single culprit. Although Dermatophilus congolensis has historically been blamed as the main cause, more recent studies have found that it is only present in a proportion of cases. Other bacteria such as Staphylococcus aureus, Pseudomonas spp., and fungal organisms are also frequently isolated in affected horses. This suggests that mud fever is often a polymicrobial infection, meaning that several types of bacteria and microbes are working together or opportunistically invading once the skin barrier is compromised.

Healthy horse skin has natural oils and protective barriers, but constant wetness from mud and rain softens the skin and creates tiny abrasions. These small breaks in the skin provide entry points for bacteria. The winter months in the UK bring the perfect storm: lots of rain, mud, and often horses with longer hair or “feathers” on their legs that trap moisture. Horses with thick leg hair (feathers) can be at higher risk because mud clings to the hair and the skin stays damp longer. On the other hand, horses with very delicate or pink skin (for example, white socks) may also be more susceptible since their skin is more sensitive.

Aside from wet conditions, there are several risk factors that can make mud fever more likely. Standing in dirty, damp bedding can irritate the skin too, so horses kept in unclean stables might develop pastern dermatitis even without muddy fields. Over-washing the legs is another risk – it sounds counterintuitive, but washing a horse’s legs every day, especially without drying them thoroughly, can actually increase the chance of mud fever. Excess water and scrubbing remove protective oils and soften the skin, just like mud would. Also, if a horse has any small cuts or grazes on the lower legs, these can be entry points for bacteria. Even mites can play a role: horses itchy from feather mites may stamp and chew their legs, causing breaks in the skin that invite infection. And as with many ailments, a horse with a weakened immune system or an underlying condition (like Cushing’s disease) might have a harder time fighting off minor infections, turning a tiny crack into a full-blown case of mud fever.

Prevention: Keeping Mud Fever at Bay

Preventing mud fever is far easier than treating it. The aim is to protect your horse’s legs from prolonged moisture and mud and to maintain healthy skin. Here are some practical prevention strategies:

• Dry Environment: Limit the time your horse spends standing in deep mud or wet ground. Provide a dry area in the field (e.g. use mats or gravel at gateways and feeding spots) so your horse isn’t always ankle-deep in muck. If possible, let them have part of the day on drier ground or bring them into a stable or yard to give their legs a break. A field shelter can also help the horse get out of rain. In the stable, keep bedding clean and dry – remove wet bedding daily so your horse isn’t standing on soiled, damp straw or shavings. Good stable and pasture hygiene goes a long way to keeping skin healthy.
• Leg Care Routine: During muddy seasons, develop a sensible leg care routine. Many owners wonder if they should wash their horse’s legs after coming in from the field. Here’s the balanced approach: If the mud on the legs is very wet and thick, you can hose or wash it off – but use lukewarm water, a gentle antiseptic wash, and always dry the legs thoroughly with a clean towel right after. Standing around with wet legs is what you want to avoid. An alternative (often best for light mud) is to let the mud dry and then brush it off gently with a soft brush. This avoids excessive water on the skin. Importantly, do not shampoo or scrub your horse’s legs every single day “just to be safe” – too much washing can actually make the skin prone to cracking (and thus infection) by stripping natural oils. Save the deep cleans for when they’re really needed, and focus more on thorough drying.
• Barrier Protection: Before turnout, especially if your horse has white or sensitive pasterns, you can apply a barrier cream or ointment to the legs. These water-repellent creams (often zinc or oil-based) create a layer that mud can’t easily penetrate. Crucial tip: only put barrier cream on clean, dry legs. If you slather cream over wet, muddy skin, you’ll just seal in moisture and germs – possibly making things worse. So, towel-dry the legs first, then apply a thin layer of barrier cream before turnout. There are also spray-on barrier oils (like the traditional pig oil used on horse feathers) that can help mud slide off. This can be useful if your horse has been trimmed. Additionally, consider using waterproof turnout boots or leg wraps designed to keep mud off. These can be very effective for some horses, but make sure they fit well and check under them daily to be sure no mud or irritation has snuck in.
• Daily Inspections: Make checking your horse’s legs part of your everyday routine, especially in winter. Early signs of mud fever can be easy to miss under winter hair or dried mud. Run your hands down the back of the fetlocks and pasterns – feel for any scabs, heat, or swelling. If you catch a small scab or a bit of redness early, you can start treatment right away and prevent a minor issue from escalating. Daily hoof care is important too: constant wet conditions can also cause problems like thrush in hooves, so a quick pick and check of the feet is worthwhile. Finally, pay attention to your horse’s behavior – if they start stamping their feet or seem reluctant to let you touch their legs, they might be developing mud fever or mites, and it’s time for a closer look.

Treatment: Managing an Outbreak

Despite your best efforts, your horse might still get mud fever one day – it happens to the best of us! Treatment requires a bit of effort and patience, but it’s very doable and usually effective. The primary goals are to kill or remove the bacteria, keep the area clean and dry, and support the skin’s healing. Here’s how to tackle it:

1. Move to a Dry Area: First, bring your horse into a clean, dry environment. Keep them out of the mud until the sores have healed. Ongoing exposure to wet and dirt will just feed the infection, so a dry stable or yard turnout is best during treatment. Ensure their bedding is fresh and dry; consider using a deep bed to cushion any swollen legs and encourage your horse to lie down comfortably.
2. Soften and Clean the Scabs: The next step is the most hands-on: you need to clean the affected skin and loosen those painful scabs. Use a gentle antiseptic wash – commonly a dilute solution of chlorhexidine (Hibiscrub) or povidone-iodine, as recommended by your vet. Massage the soapy solution onto the scabby areas and let it sit for around 5–10 minutes (if your horse tolerates it) to really soften up the scabs and let the antiseptic do its job. Never use cold water on the legs in winter, as it can chill your horse – warm water is not only kinder but also helps open pores and loosen debris. After soaking, rinse thoroughly with clean water to get all soap residue off, since leftover disinfectant can irritate the skin if not removed. Now, gently pat the area dry with clean towels or paper towels. Take your time to get the legs as dry as possible, because moisture is the enemy here. If your horse has heavy feathering, you might need to carefully trim the hair away from the sores (you can ask your vet or a professional to do this, and in severe cases sedation might be needed). Clipping the hair will make cleaning and drying much easier.
3. Scab Removal: Once the area is clean and the scabs have been softened by washing, start to remove the scabs that will come off without force. Often, you can gently pick them off with your fingers or wipe them away with gauze. Removing scabs is important because the bacteria often hide beneath them, and healing won’t progress until that infected material is gone. However, be very gentle – if a scab does not lift away easily, do not rip it off and make the skin bleed. You can repeat the soaking process again later to further loosen stubborn scabs rather than causing your horse pain. Some people like to apply an ointment to soften scabs overnight (for example, a cream bandaged on under plastic wrap as advised by vets) and then remove them the next day, but only do this after consulting with your vet, as it must be done carefully. The main point is to get the crusts off gradually so healthy skin can recover.
4. Topical Treatment: After cleansing and de-scabbing, make sure the skin is dry, then apply a topical treatment to help kill remaining bacteria and protect the skin. Your vet might prescribe a special cream or powder. Common treatments include antibacterial and antifungal creams (sometimes combined with a mild steroid to reduce inflammation). A useful tip from recent veterinary guidance: use a thin layer of cream that can be absorbed, rather than a thick, greasy layer that cuts off air circulation. The bacteria that cause mud fever actually thrive in airless, damp environments, so slathering on heavy ointments can backfire. Instead, apply just enough of a vet-recommended cream to cover the affected skin. In mild cases, an over-the-counter antibacterial cream might suffice, but for more serious infections, a prescription antibiotic ointment or even oral antibiotics could be needed – your vet will guide you here.
5. Bandaging and Rest: If the sores are in an area that can be bandaged (like the pastern and fetlock), you can use dry, sterile dressings or stable bandages to cover the area after applying the cream. This can keep the legs clean and prevent dirt from getting into the wounds, and it also absorbs any oozing discharge. Make sure you only bandage dry legs – never wrap wet legs, as this would macerate the skin. Change bandages daily (or as directed by your vet), and always put on a fresh, clean bandage; never reuse one without washing it. Some modern bandage pads contain antibacterial properties which might be useful in stubborn cases. If your horse lives outside, full bandaging might not be feasible (bandages would get wet and muddy quickly). In that case, you may need to keep them in a controlled environment until the worst is over, or use turnout-specific leg wraps that are designed to stay dry.
6. Observe and Repeat: Treating mud fever isn’t a one-and-done task – you will need to repeat the cleaning and cream application daily (or as advised) until the infection is fully resolved. Each day, gently clean away any new dirt, remove new scabs that have loosened, and apply fresh cream. With each session, you should see fewer new scabs forming as the skin heals. Keep the horse on dry ground until the skin has fully healed and new hair is growing back. This process can take anywhere from a week or two for mild cases, up to several weeks for severe cases. Patience is key. Continue to check for swelling or signs the infection is spreading.

When to Call the Vet

You should involve a vet early in the case of mud fever, especially if you are unsure about the severity. It’s wise to call your vet as soon as you suspect mud fever, because they can confirm the diagnosis and advise the best treatment plan. Mild cases caught very early might be managed at home with over-the-counter products and diligent care. However, you must call the vet without delay if you observe any of the following:

• Severe swelling or lameness: If your horse’s leg is significantly swollen or they are limping, the infection could be deep or spreading (possibly into the tissue causing cellulitis or lymphangitis). This often requires systemic treatment (like antibiotics or anti-inflammatories) that only a vet can provide.
• No improvement or worsening after a few days: If you’ve been cleaning and treating for several days and the area is getting larger, more painful, or isn’t improving, a vet visit is needed. The vet might take a skin scraping or swab to identify the exact bacteria involved and test which antibiotics will work best. They can also check if there is a fungal component or something else complicating the picture.
• Horse is very uncomfortable or multiple legs are affected: Extreme pain, reluctance to move, or spreading lesions could mean your horse needs more aggressive treatment or even pain relief to keep them comfortable. Additionally, if more than one leg has mud fever, it’s definitely time for professional guidance (managing a horse with multiple sore legs can be tricky and they may need rest and nursing care).
• Suspicion of other conditions: Sometimes what looks like mud fever could be something else (like vasculitis or an allergic reaction). If the sores are unusual or not responding, a vet can rule out other diseases. Also, as mentioned, mites can cause similar scabbing – your vet can prescribe treatments for mites if needed (for example, medicated washes or injections).

Conclusion

Mud fever can certainly be a frustrating issue, but with knowledge and prompt care, it’s manageable. Through muddy winters and beyond, focus on prevention first: keep those legs as clean and dry as practical, use barriers against mud, and check your horse regularly. If mud fever strikes, be ready to step in with gentle treatment – clean, dry, medicate, and repeat. Most horses recover well with diligent care. And perhaps the silver lining: this can be a bonding time with your horse, as all those leg soaks and bandage changes mean extra TLC! With the latest guidance and a proactive approach, you can help your horse stay comfortable and mud-fever free as much as possible.

Sources and References (2019–2025):

1. British Horse Society – Mud Fever: Causes, Signs & Treatment. Last reviewed Nov 2024.
2. RSPCA – Winter Horse Care (Mud Fever Prevention). RSPCA Advice, 2025.
3. Blue Cross – Caring for Your Horse in Wet Weather. Blue Cross Horse Advice, Jul 2023.
4. World Horse Welfare – Mud Fever in Horses (Treatment Guidance). World Horse Welfare Advice, 2023.
5. Horse & Hound Veterinary Features, 2022–2024.
6. Equine Veterinary Journal – Dermatophilosis and Pastern Dermatitis in UK Horses, 2023.