What is “Mud Fever”?

‘Mud Fever’ is a common skin condition usually affecting the legs of a horse, typically the heels and pasterns.  Most commonly seen during wet winter conditions, Mud Fever, which is also known as greasy heel, cracked heels or scratches, is more correctly termed Pastern Dermatitis. 

Pastern Dermatitis is caused by bacteria including Staphylococcus and Dermatophylus species.  These bacteria live on the healthy skin of horses without causing a problem, until the winter months when horses spend time stood in wet, muddy conditions for prolonged periods.  This results in softening of the skin and a disruption of the natural skin defences, along with small cuts and scratches, which allows bacteria to penetrate the skin and infection to establish.

Signs and Symptoms

Mud fever may vary in severity, ranging from a few small sores to extensive thick scabs, inflammation, cracked skin, hair loss and purulent discharge.

The condition can be very painful and may result in lameness and behaviour changes; such as becoming difficult to shoe or handle the legs and a reluctance to pick up their feet.  The affected limbs may be markedly swollen with swelling tracking up the limb as far as the knee.  In rare cases, secondary conditions such as lymphangitis may develop.

Treatment of Mud Fever

While there are a multitude of products available at tack shops and saddlers to treat and prevent mud fever, this painful condition can be difficult to resolve and in many cases does require veterinary intervention. 

In mild cases, topical treatment alone may be enough, combined with careful environmental management, but more severe cases will usually require oral antibiotics and anti-inflammatory medication.

Affected horses must be kept out of wet muddy conditions until their lesions have totally healed.  Stable or yard rest is usually required to ensure the legs stay clean and dry.

After initially clipping and cleaning the lesions, the crusts should be soaked with an antibacterial solution to remove them and allow penetration of topical treatments directly to the skin.  This process can be very painful, and sedation may be required.

Daily application of prescribed topical creams is then continued until the lesions have totally resolved and the skin has healed.

Prevention of Mud Fever

The main aim in preventing mud fever is to prevent the legs from becoming saturated and muddy.  In practice this can be very difficult, but steps such as putting chippings down in gateways and trying to avoid excessive poaching of fields are worthy of consideration.

Topical barrier creams can seem like a good idea, but may cause more problems than they solve, as they may hold moisture closer to the skin, providing the perfect environment for bacterial infection to recur.

Counter-intuitively, washing off muddy legs when horses come in from the field is best avoided.  The ideal management is to dry the legs as quickly as possible – straw beds are better at encouraging drying than other substrates, but may not always be ideal for other reasons.  Alternatively, drying leg wraps can be applied directly over wet, muddy legs.  When the legs are dry the mud can then be brushed off.  This management technique has proven to be the most reliable way of preventing Med Fever.

For further advice regarding mud fever treatment or prevention please contact the Equine team on 01363 772860