Mud Fever in Horses: What It Is & How to Treat It

Mud fever is a dermatological condition that’s typically found on the rear of the fetlock region. It’s also known as pastern dermatitis, or cracked heels, due to its scabby presentation.

The condition gets its common name from the fact it tends to appear during times when pastures and paddocks are muddy. However, mud itself is not the culprit so much as it’s the collision of two conditions that combine together and result in a crusty, painful skin condition for the horse. 

Veteran horse owners will say that mud fever is near the top of the list in terms of skin conditions they don’t want to see. It’s a nuisance, difficult to heal once it takes hold, and can make a horse lame. Fortunately, it’s possible to prevent mud fever by taking precautions, such as using mud fever boots, and engaging in post-turnout maintenance of your horse’s legs.

Read on to learn more about the condition, how to treat it, and how to prevent it from taking hold. 

Table of Contents

    As always, the information in this article is for informational purposes only and should not be considered medical advice for your horse. You should always consult with your vet when treating your horse.

    The Basics of Mud Fever

    The condition gets the mud part of its name from the fact that it’s most often seen during wet seasons that turn sand and soil into a sloppy and muddy mess. Horses that spend time standing around in these conditions are at higher risk of developing mud fever, although it’s not a guarantee that the condition will take hold. If a horse is caked in mud that’s abrasive, it’s more likely to develop mud fever.

    Moisture and grit are two of the properties that make up mud. Mud will cake and dry on the fetlock joint, and abrade if it contains a lot of sand or grit. The action of a horse’s leg causes the mud to abrade the skin, opening up scratches that allow bacteria to enter into the skin. Once the bacteria has a point of entry into the skin, it can take advantage of the favorable conditions to create an infection. 

    The fever part of the name comes from the heat that is generated by the scabs that develop after the bacteria has taken hold. The horse’s body mounts an immune defense/offense to eliminate the bacteria and heal itself. Scabs form to cover the skin breaks caused by the bacteria, and an inflammatory reaction also sets in. Even though the horse isn’t experiencing a fever, the area will be hot to the touch, hence the use of the word fever

    What causes mud fever specifically?

    The condition is mainly caused by a type of bacteria called dermatophilus congolensis, but it can be caused by other types of bacteria. Mites can also cause mud fever by chewing holes in the skin, allowing bacteria to enter the skin layer. 

    Can a horse become lame from mud fever?

    Yes, a horse can become lame and look as if it has a serious lower leg problem from the pain of mud fever. Before you go looking for an injury, check the pastern joint for heat and swelling along with the following signs of mud fever. 

    What are the Signs of Mud Fever in Horses?

    Before you touch your horse’s leg for an inspection, do a visual check first. The condition can be painful and your horse may flinch or kick when you go to touch the affected area. If you can’t see the signs, stand to the side of your horse and slowly draw your hand down their leg so they know you’re there and you’re not intending to hurt them. You need to investigate the condition, but also avoid a kick. Be careful and always be aware of your horse’s reaction to your inspection. 

    When looking for the signs of mud fever, remember that it is restricted to the lower fetlock joint and heel bulbs. The signs of mud fever in horses include:

    • Crusty scabs
    • Scratches
    • Lesions or open sores
    • Bleeding
    • Clear discharge
    • Swelling
    • Lameness

    Untreated mud fever can reach an advanced stage that appears as scabs and lesions that creep up the hindquarters. If the mud fever reaches this stage, the horse is at risk of contracting a staph infection or cellulitis. 

    Treating Mud Fever

    The steps for treating mud fever depend on the severity of the condition. In order to eliminate the infection, you need to use antibacterials and keep the area dry. If the condition is severe, you’ll need help from your veterinarian in the form of prescription medications to kill the bacteria with external and internal assistance. That is, you may need to use antibacterial soap, steroid cream to control inflammation, and oral antibiotics to boost the horse’s immune system. Your vet may also prescribe a treatment that requires bandaging and keeping the horse in its stall. 

    Removing the scabs is the most important part of treatment

    The scabs that develop as the result of the bacterial infection also serve to protect the bacteria from attempts to kill it off. The best way to treat the issue is to remove the scabs and expose the infected area to the air. Exposing the bacteria to air serves to kill it off as it’s anaerobic and thrives in the low-oxygen environment provided by the scabs. 

    How long does it take to treat mud fever?

    Treatment can last for anywhere between a few days to a couple of weeks, but the amount of time it takes to heal the lesions depends on various factors. You may find yourself treating the affected area for weeks before the issue resolves. 

    What is a natural remedy for mud fever?

    You can use coconut oil or Vaseline to prevent the appearance of mud fever, but they won’t work after mud fever has set in. You want to kill the bacteria, and natural remedies may not be strong enough to reliably kill off the organisms. Treatment with medication is the best approach to get rid of the condition. 

    Does mud fever go away on its own?

    Mud fever has the potential to go away on its own, but it’s not a good idea to ignore the condition, as it can spread up your horse’s legs and cause cellulitis. It’s far better to get on top of the infection and stop the problem from getting worse, even if it makes your horse uncomfortable.

    Risk Factors for Mud Fever

    Most horses grow hair known as feathers that cover the back of the pastern joint. Horses that have thick feathers, or have fully feathered lower legs as a breed trait, are at higher risk of developing mud fever.

    The feathers trap mud, and the mud causes the feathers to cling to the fetlocks and create an abrasive action. This causes the skin to become raw or develop scratches, allowing the bacteria into the subdermal layers. The feathers, which are supposed to be protective, become a liability, especially on horses with white socks. 

    Certain coat colors make a horse more susceptible to contracting mud fever

    It’s a known fact that horses with light-colored coats and pink skin are more susceptible to skin conditions than horses with darker-colored coats and dark skin. This is true for mud fever, and horses with white socks have an increased risk of contracting the condition.

    It’s not known as to why horses with white socks are more vulnerable, but it is something to be on the lookout for. One potential cause is when a horse has altered liver function and white skin. This results in photosensitivity that causes the skin to burn and crack. It’s worth noting that light-colored horses and ones with white socks are prone to mud fever even when they’re not bathed frequently.

    Frequent washing

    Horses who are bathed frequently are at risk of having dry skin due to the loss of their natural oils from shampooing. In addition, horses with white socks that are washed frequently are also at an increased risk of contracting mud fever. Once the skin dries out, it’s more likely to crack or flake open and create a break in the skin’s defensive barrier. Cuts then form and allow bacteria to take hold. 

    How to Prevent Mud Fever

    You may be tempted to limit your horse’s turnout during muddy or wet conditions as a way of preventing mud fever. The fact is, muddy conditions are not the direct cause of mud fever, even though there is a correlation.

    Many horses do fine with muddy conditions and never have an episode, while other horses are seemingly prone to getting the condition when they look at mud! Indoor turnout is one potential solution, but if that turnout also happens to be the riding arena, it’s not going to be adequate.

    So, how do you prevent mud fever?

    1. Clip off feathers and keep fetlock hair short during wet conditions

    A horse that has less hair on its fetlock has a lower risk of contracting mud fever. The hair is too short to hold mud against the skin, and prevents abrasion. 

    2. Use barrier cream

    Barrier cream is a thick paste that stays in place and contains zinc oxide. The cream prevents mud from caking and the zinc oxide adds protection against UV damage on white socks.

    3. Apply mud fever turnout boots

    Mud fever boots cover your horse’s legs from the hoof all the way to below the knee. The design prevents mud from caking on the legs and fetlock joints, and keeps your horse’s legs dry and clean. 

    4. Rinse and dry legs after turnout

    Wash your horse’s legs after bringing them in from turnout, then dry them off. This prevents caked mud from drying in place and causing sores.

    In Summary

    Mud fever is a dermatological condition that requires persistent treatment to resolve it. The condition is stubborn when it comes to killing off the bacteria that cause mud fever, which means you’ll be spending some time at the barn treating your horse.

    Fortunately, it’s preventable with the use of turnout boots and removal of caked mud to prevent it from drying and abrading the skin. 

    Muddy conditions aren’t always a guarantee that your horse is going to develop mud fever, but you can get ahead of its appearance by taking appropriate precautions before you let your horse out into the turnout. This is one of those situations where an ounce of caution can prevent a pound of cure.

    Leave a Comment

    This site uses Akismet to reduce spam. Learn how your comment data is processed.