Mud fever

Traditionally, mud fever has been associated with the wet muddy conditions we see in the winter. However, it can occur throughout other times of the year.

What is mud fever?

Mud fever, also known as pastern dermatitis or ‘cracked heels’ is a skin condition generally caused by a bacteria called Dermatophilosis Congolensis. This bug is what’s known as a skin commensal. This means it lives on the surface of normal, healthy horse skin. When repeated wetting (or rubbing) of the skin happens it causes an issue where tiny areas of damage then allow the bacteria to invade deeper into the skin. It tends to affect the pastern and cannon regions and white limbs are generally more susceptible.

It usually starts as red, sore areas of skin that can progress to thick scabs and weeping sores. This can be very painful to touch and can sometimes cause lameness. Left untreated, the infection can track deeper into the tissues under the skin, causing a painful condition known as cellulitis. This is characterised by a hot, swollen and very painful limb.

How do we treat mud fever?

If your horse has mud fever it is important that the affected areas are thoroughly washed with hand-hot, dilute antimicrobial skin cleanser solution, such as Hibiscrub. This should be worked into the skin and as many of the scabs lifted away as possible. As this can be painful for the horse, sedation may be needed to facilitate this. After rinsing away the skin cleanser solution it is vital that the skin is dried thoroughly. Using clean towels, paper towels and possibly even a hair drier can help.

Once the areas are clean and dry a medicated cream will need to be applied. Your vet can advise on a suitable cream. Most cases can be treated solely with a cream. However, cases with very deep sores or cellulitis may require oral or injectable antibiotics.

When dealing with a case of mud fever, your vet will also check your horse for feather mites and treat these if necessary as these can exacerbate the condition.

How can it be prevented?

As with most things, prevention is better than cure. There are various management techniques that can be employed to prevent mud fever. Avoiding wet, muddy conditions is the key. Keeping gateways and shelters mud free (try putting down wood chip in high traffic areas) and bringing horses off muddy pasture is a good idea.

The use of protective mud fever boots and barrier creams can help if your horse is turned out. However, the skin MUST be clean and completely dry before applying any barrier creams or boots.

If your horse’s legs do get muddy remember that wet, softened skin provides the perfect conditions for the bacteria to grow and multiply so it is no good religiously washing your horse’s legs clean everyday unless they are thoroughly dried too. If possible, it is far better to let the mud dry naturally and then brush it off.

The clipping of hairy legs can be very useful as it helps to keep the legs clean and dry and provides better visibility so any sores are likely to be noticed and treated earlier. If your horse has very heavy feathers and lives out 24/7, however, you may be better to leave the feathers on to provide some degree of protection to the legs, provided you do not wash the legs unnecessarily.