Time Again to Tackle Mud Fever: Zoe Satsias BVM&S MRCVS Discusses Causes and Prevention

At this time of year, a large majority of horses are affected by this nasty and frustrating condition.

Mud fever is an infection of the skin by Dermatophilus congolensis, an organism found naturally on the horse’s skin. It tends to lie dormant in the skin and is activated once it is damaged, usually in wet and muddy conditions. Other causes of mud fever include excessive washing of your horse’s lower limbs before and after work, without thoroughly drying afterwards, as well as skin trauma from ill-fitting boots, chaffing from sand or sawdust and a suppressed immune system (secondary to another condition).

Mud fever is usually very easy to recognise. Hair tends to get matted and crusty scabs are present, which once removed reveal ulcerated lesions and/or purulent discharge. If left untreated, it can become very painful, with localised heat and swelling, potentially causing lameness. Severe cases will affect your horse’s demeanour, causing lethargy and a loss in appetite.

Treating mud fever is a struggle in wet conditions, as keeping the limb clean and dry is a must. Scabs should be softened with warm water and gently removed. The underlying skin should be scrubbed clean with a disinfectant, such as diluted chlorhexidene, and the limb then dried thoroughly. Any antibacterial ointment can then be applied to the affected region, along with a moisture-repellent cream such as zinc oxide or Sudacrem. It is of utmost importance that the limb is dry before application of these creams. Bandaging is also an option, though stabling is advised so that the bandage does not get wet. Systemic antibiotics may be necessary in severe cases.

Prevention is very challenging but definitely worth it. Consider disinfecting surfaces and equipment used on your horse periodically. Towel dry limbs when washed and consider using a topical barrier cream, such as petroleum jelly, to keep the moisture out. Once infection is established, stabling might be your only option. Be observant. The sooner you spot the first signs of mud fever, the faster you can get rid of it.