Mud Fever - an unwelcome skin condition

Mud fever is a skin condition that causes irritation, soreness, matted areas of hair, and scabs. It is known also by other names, including dermatitis, greasy heels and cracked heels. The condition is often diagnosed in the autumn/winter months under consistent exposure to wet and muddy conditions.

Signs

Mud fever commonly forms on the pasterns (between the fetlock and the hoof) and the heels. Infections can develop underneath the scabs and swelling may be visible in severe cases. Mud fever can be painful, and the not pleasant for the horse to be touched in the area affected.

Check limbs daily to spot any signs of mud fever early when it is easier to manage.

Common signs of mud fever include:

Crusty scabs on the heels or lower legs.
Broken and/or damaged skin.
Matted hair or patches of hair loss with raw skin underneath.
A creamy, white, yellow, or green discharge between the skin and the scabs.
Heat, pain and swelling in the lower limb.
In severe cases, lameness may also be seen.

Mud fever can also occur on the belly, and on the back – this is called rain scald. Rain scald can also be triggered by spending long periods in damp, mild conditions, or from excessive sweating under tack or rugs. Scabs form along the neck, back and hindquarters. Rain scald is characterised by these scabs coming off with tufts of hair. It is important to speak to a vet for advice and to confirm the signs are not mistaken for ringworm, for example, which is in contrast a highly contagious fungal infection and must be managed differently.

Causes

Mud fever is common in the winter months and is most often caused by bacteria. Wet conditions causes the skin to soften and mud rubs against this softened skin causing damage to the surface where bacteria can enter.

Another cause of mud fever are leg mites which break the skin enabling the entry of bacteria. Horses/ponies with thick feathers are more at risk of leg mites and they may stamp their legs because they’re very itchy. If mites are suspected, speak to your vet for further advice.

Risk factors

Damaged skin is more susceptible to bacteria, and therefore mud fever.

Factors that may cause damage to equine skin

Standing in muddy or wet conditions or dirty bedding for long periods
Regularly washing the limbs, especially if not dried afterwards. Recommend instead allowing mud to dry and then brushing it off. If washing is required, then thoroughly dry the skin.
Broken or damaged skin due to a wound.

Characteristics that make some horses/ponies more prone to developing mud fever:

White legs - pink skin under white markings is often more sensitive than dark skin.
Having a weakened immune system – usually secondary to another condition, for example Cushing’s Disease, and therefore less able to prevent and fight off infections and more prone to health conditions. If these equines suffer from mud fever, it can be more difficult to treat.

Treatment

Liaise with a vet as soon as mud fever is suspected to attain an accurate diagnosis and ensure treatment is tailored to the animal’s needs.

A general treatment plan might include:

Bringing the horse/pony in out of the muddy and wet conditions to keep skin clean and dry.
Removing the scabs to gain easier access to the skin and allow air to reach the skin and help the area heal. However, care is required as it can be very uncomfortable and sedation may be necessary. Loose scabs may be gently removed, but scabs should not be forcibly removed unless advised by the vet.
Clean the affected area at least twice a day using a mild disinfectant, such as dilute Hibiscrub, then rinse with water and pat the leg dry with a clean towel.
Thick feathers you may need to be carefully clipped to expose skin to the air and make it easier to clean and treat it.
Applying stable bandages to dry legs can help keep them clean, provide support and reduce any potential swelling.

Severe mud fever may require repeat treatments and cream applied to the skin as advised by the vet. If mites or a fungal infection have triggered the condition, individual treatment for these causes may be required. A blood test may be required to identify an underlying disease. If the mud fever isn’t clearing up, a swab can also be taken to check for bacterial growth and sensitivity, allowing for the appropriate use of antibiotics. Anti-inflammatories may be recommended, depending on the clinical signs and overall health of the horse/ pony.

Reducing Incidence

Management can help to reduce the risk of developing mud fever, aimed at avoiding the underlying causes:

Avoid leaving equines standing in wet and muddy conditions for long periods, ensuring they have somewhere dry to stand for at least part of the day.
Rotate fields to reduce poaching and consider placing hardcore where horses gather, i.e. gateways /water and feed troughs.
Fence off any exceptionally muddy areas.
Avoid washing limbs when bringing in from the field and instead wait until the mud is dry, and brush off using a soft bristled brush. If limbs are washed, dry them thoroughly afterwards using a clean, dry towel.
Barrier creams can be used before turnout, to create a protective layer between the skin and the mud. But, ensure skin is dry and clean before application, otherwise the perfect environment for bacteria to grow can be created between the skin and the cream.
Treat any underlying conditions such as mites, fungal infections or wounds as a priority.

Be aware of Cushings Disease and speak to the vet for further advice where this is suspected.