RAIN SCALD AND GREASY HEEL

With the arrival of the rain, owners may start to see problems associated with wet weather. Rain scald and greasy heel are caused by a bacterial (or sometimes a fungal component) infection of the skin resulting in the formation of matted scabs affecting the back, rump and lower limbs.

The bacteria is most often responsible is a member of the Dermatophilus family. Prolonged wetting of the skin, as occurs in wet weather, allows the bacteria to invade the surface layer of the skin and establish an infection.

In mild cases, the horse may just have a few flat scabs containing mats of hair. When the scabs are removed the underneath surface is slightly moist and sometimes raw. In severe cases the coat will feel hard and painful and will consist of many scabs lying next to each other. If the scabs are gently removed, the horse may be left with a large area of bare, raw, skin.

When the infection affects the lower limbs it is called ‘mud fever’ or ‘greasy heel’ and similar scabby lesions will be found, particularly on the back of the pastern and fetlock and the limbs may become swollen.
It is possible for owners to confuse cases of rain scald with ringworm, some parasitic conditions and possibly photosensitisation with rain scald.

In order to treat rain scald or greasy heel affected areas should be gently washed with a mild disinfectant shampoo or solution e.g. chlorhexidine or povidone iodine. As many of the scabs as possible should be removed without causing excessive discomfort to the horse. Sometimes this can’t be achieved in one session but it is essential that all scabs are removed. Covering lesions or bandaging limbs with a good layer of antibiotic cream for 24 hours will soften remaining scabs and allow their removal. The skin should be dried or allowed to dry completely and antibiotic spray or ointment is applied. In severe cases we may administer antibiotics or anti inflammatories. After scabs are removed, keeping the horse dry will help result in resolution of the condition.

As the bacteria multiplies best in warm, wet conditions, keeping the horse stabled, sheltered, or rugged with a waterproof rug during wet weather (ensure rug is fully water proof but breathable and remove whenever possible to air and check horse), in order to protect the skin from prolonged wetting and help prevent infection. If the problem involves the limbs it is important to keep them mud free and if stabled, on clean dry bedding.