Mud fever, also known as pastern dermatitis, is a non-contagious (which means it doesn’t spread from one horse to another or to people) skin condition that causes irritation, soreness, matted areas of hair and scabs that form on the horse’s lower legs. Mud fever commonly forms on the pastern (between the fetlock and the hoof) and the heel. Infections can develop underneath the scabs and you may see swelling of the leg in severe cases. Mud fever can be painful, and the horse may not tolerate the area being touched. Pink skin under white legs can be more commonly affected compared to dark skin.
Mud fever is most often caused by bacteria and is common in the winter months when the horse is exposed to persistent wet, muddy conditions. This is because the wet conditions cause the skin to soften and mud rubs against this softened skin causing abrasions to the surface where bacteria can enter. There can be other causes of mud fever such as leg mites which damage the skin and enable bacteria to enter. Horses with feathers are more at risk of leg mites and you will see them stamp their legs because they’re very itchy. Speak to your vet for advice.
Constantly washing and wetting the horse’s legs can also cause the skin to soften and weaken and increases the risk of mud fever developing. There are many differing opinions as to what to do with wet, muddy legs. It is recommended to allow the mud to dry and then brush it off. If washing is required, then it is important to thoroughly dry the skin.
Bring your horse in out of the muddy and wet conditions if you find signs of mud fever and contact your vet for advice. They may suggest treating mild mud fever yourself by cleansing the affected area with an antibacterial solution such as dilute Hibiscrub (Chlorhexidine) and warm water to help gradually remove the softened scabs. The area should then be rinsed with warm water and dried thoroughly, and the process repeated as appropriate. This process can be difficult if your horse has thick feathers as you can’t get to the skin very easily so your vet is likely to advise clipping. Be aware that removing the scabs can be painful to the horse so sedation maybe required. Severe mud fever may require repeat treatments and cream applied to the skin. Your vet will be able to advise the course of action and treatment plan.
You can help prevent mud fever by bringing horses in off the pasture every day to allow their legs to dry so mud can be brushed off. This also gives you a chance to check for injuries and monitor for signs of mud fever to enable treatment to begin at the earliest possible opportunity. If this isn’t possible, maintain good pasture management to help limit poaching and monitor for any signs of mud fever. Be wary of barrier creams for prevention as they can provide a perfect environment for bacteria to grow in between the skin and the cream.
Horses with a reduced immune function (immunosuppression), such as those with Cushing’s disease, can make mud fever difficult to treat.
Mud fever formed on a horse’s pastern