Mud Fever: The Symptoms and Management

What is Mud Fever?

Mud fever; also known as pastern dermatitis or ‘cracked heels’ is hugely prevalent at this time of year.

As the rain continues to fall our paddocks become inevitably waterlogged and poached, creating the perfect environment for this skin condition to develop.

The mud coats the lower limbs breaking down the skins’ natural barrier. The skin then becomes soft, fragile and prone to damage.

Horses with white legs are more susceptible.

What are the Signs?

Any small break in the skin caused by abrasions from the grit in the mud or sand from arenas enables the bacteria to enter.

The resulting symptoms are heat, swelling and crusty pink hairless lesions around the pastern and heel bulbs.

The bacteria most commonly responsible for this infection is Dermatophilus congolensis. Left untreated infection can spread up the limb causing cellulitis.

This is a painful condition resulting in lameness and swelling of the affected limb.

Prevention is Better Than Cure

Prevention is preferable and keeping your horses’ legs clean and dry is the best way to control mud fever.

However, this is easier said than done at this time of year.

  • Clipping very hairy legs will reduce the accumulation of wet mud around the lower limb and allow better assessment for developing lesions.
  • Managing areas in the field prone to deep mud; particularly around gateways and water troughs. By putting down hardcore or woodchip this will reduce the amount of mud coming into contact with the legs.
  • Hosing legs off on a daily basis is not advised unless they are going to be thoroughly dried afterwards. This process will lengthen the amount of time the hair and skin is damp. Instead, allow the mud to dry and then brush it off.

There are many products available that are aimed at preventing mud fever as they work to protect the skin from moisture.

However these products should not be used if mud fever lesions have already developed as they can slow down the healing process. 

It is imperative that horses’ legs are checked frequently to enable prompt diagnosis and treatment.

My Horse Has Mud Fever, What Do I Do?

If mud fever is identified then bring your horse out of the mud and into a stable or barn.

First clip the hair around the lesions and remove any scabs with a dilute Hibiscrub wash as this will allow more accurate and effective application of treatments.

Thoroughly dry the leg after removing the scabs. If lesions are noticed on more than one leg, then be sure to dry each leg with a different towel, in order to prevent the spread of the infection.

Most of the time mud fever can be managed topically with prescription antibiotic creams such as Flamazine but sometimes oral or injectable antibiotics are required.

Your horse should then remain on box rest or in an enclosed yard/barn area until the lesions have been treated and the skins’ barrier has been restored.

If you are unsure or your horse is lame, then please contact your vet as further investigations or veterinary prescription treatment may be required.

If your horse isn’t responding to treatment then there can be other rare causes of lesions of this nature, particularly if only affecting white haired skin, that may need to be investigated and ruled out. 

Mud Fever

Mud fever (also known as cracked heels or greasy heels) is a condition of the skin on the lower legs which typically occurs during wet weather in horses who are turned out. It is a bacterial infection caused by a particular bacteria called Dermatophilus. These bacteria live within the mud, with some fields being more severely infected than normal. The spores can persist for several years within the mud. The bacteria will not invade healthy skin, however skin which is constantly exposed to wet conditions will gradually become chapped and sore, allowing the bacteria to enter the skin and set up a localised infection.

Which horses are most severely affected?

Any horse can be affected by mud fever, it is certainly not a condition that is limited to those turned out in extreme muddy conditions. However those with fine limbs, ‘thin skinned’ breeds (such as Arabs and TBs) and those with white fetlocks and pasterns are generally most severely affected. Cobs with heavy feathers may suffer less due to the protection offered by the feathers.

How will I recognise if my horse has mud fever?

Typically the horse presents with scabs on the pasterns which cause the hair to clump together (has the appearance of a paintbrush). When these scabs are removed the skin underneath will have a layer of pus. Occasionally there will be swelling of the whole lower limb and in severe cases the horse may show signs of lameness. It is important not to confuse mud fever with leg mites, the latter normally cause scabs higher up the leg, with irritation and stamping of the legs a common feature.

How should I treat mud fever?

Early recognition and treatment is important to prevent the condition from progressing. In the initial stages the lower limb should be washed daily with an antibacterial shampoo (Malaseb or Hibiscrub solution work best). The legs should be dried well afterwards, ideally with paper towels which are disposed of afterwards- the scabs can remain infective for years in the environment so using the same towel to dry the legs daily will cause recurrence of infection. The legs should be clipped (with sedation if the horse is fractious or painful) and the scabs removed once they are softened. This stage is vital as the bacteria live under the scabs, so removal will allow the bacteria to be exposed to the antibacterial creams and shampoos. Dispose of the scabs carefully, they carry the mud fever bacteria! An antibacterial cream such as flamazine (prescription only) can be applied once the scabs are removed. Management at this stage is important, ideally the horse needs to be stabled in clean and dry environment. Continuing to turn the horse out when trying to manage mud fever almost always results in very slow improvement or sometimes deterioration. In the event of lameness or swelling the horse should be examined by a veterinary surgeon as may require antibiotics.

How can I prevent mud fever?

Once a horse has suffered from one bout of mud fever it is usually prone to future bouts, therefore, as with many things, prevention is better than cure! Removing mud from the horses legs is important, but hosing the legs creates a wet environment which allows the mud fever bacteria to flourish! Therefore the best way to remove mud is to allow the legs to dry and then to brush the mud away with a dandy brush. Covering legs to prevent mud fever can work but if the leg covers are not breathable then the warm, wet conditions will encourage bacterial growth. An oil based barrier cream such as Vaseline can be applied to legs before turn out. Placing rubber matting around water troughs and gateways can prevent severe muddy conditions from developing! Checking the horses legs on a daily basis can allow you to intervene and instigate treatment of mud fever at the first sign.