These diseases are caused by a bacterium called Dermatophilus Congolensis, which is found in the environment and is activated by wet weather. When a horse has muddy wet legs/skin it is the perfect environment for the bacteria to gain access and multiply within the skin. The bacteria can be transmitted between horses and on equipment, so it is important to have separate equipment for each horse.

The generalised form of the disease affecting the body is known as 'rain scald' whilst the localised form affecting the lower leg is known as 'mud fever'. The lesions usually have a classic 'paintbrush' appearance with crusty lesions under the hair. The lesions can be painful but are not usually itchy.. If left untreated mud fever can lead to lameness due to deep trauma to the skin around the coronet/heels and pastern regions. Secondary cellulitis (swelling of the lower leg) can also occur and can result in antibiotics and anti-inflammatories being needed. The signs are fairly specific but a sample can be taken and used to identify the bacteria under a microscope for a definitive diagnosis.

The most important part of treatment is to reduce exposure to the muddy wet conditions, so access to a hard standing is ideal. The legs must be cleaned and dried off daily if the mud is unavoidable. If your horse has long feathers then trimming will help treatment penetrate to the skin where it is needed. All scabs must be removed, soaking stubborn scabs with a dilute solution of povodine-iodine or chlorohexidine will aid removal. All scabs and cleaning materials should be disposed of as they can be a source of infection. Whilst the infection is active the area should be cleaned twice a day, with a dilute solution of chlorohexidine. If the infection is severe, we shall need to examine the animal to start treatment with an antibiotic cream, or antibiotic powders for mixing with feed. If an antibiotic cream is needed then it should be applied to the affected area twice daily after thorough cleaning.

Keeping the animal out of muddy fields for mud fever, and out of the rain for rain scald is ideal, however, we appreciate that this is not always practical. So the use of a barrier cream, such as one containing zinc oxide can be applied to protect the skin on the legs if the horse is being turned out. A light weight full neck waterproof rug can protect against rain scald, these are now available without any filling so are suitable for most horses. Avoid excess washing or brushing of wet legs as this can damage the protective skin barrier, waiting for their legs to dry and brushing the mud off is better.

If you are at all concerned about whether your horse may needs antibiotics, please feel free to call one of our equine vets for FREE advice.