Grease is a kind of eczema and a generic term for various sorts of inflammation affecting the area from the hollow of heel to the pastern area. It can even spread up to the cannons. The first noticeable symptom is inflammation and small sores. Subsequently the skin becomes rather swollen and tender. The affected area weeps and the fluid dries, forming a scab. It can be difficult to identify the symptoms as the disease is very common in horses that have feather, such as the cold-blooded breeds and ponies. Cracks can also occur, which exacerbates the process. After a time the skin thickens and during the healing process, transverse callouses form. The horse is irritated by the itching. In severe cases there is a putrid, sweet smell. The most common causes of grease are badly cleaned stabling, very damp or muddy flooring and cold surfaces generally. Grease can also develop from an inherited weakness of the skin over the pasterns. Horses with white legs are more susceptible than others. In more unusual cases, hypersensitivity of the skin can be caused by contact allergy to, e.g., certain salves, bedding, or some agent in the environment. Skin changes in the pastern can allow various microorganisms to gain entry, which is why secondary bacterial infections, fungal infections or mites commonly develop from grease. If such infections are allowed to gain a foothold, a prominent swelling can occur on the lower part of the leg due to inflamed leg lymphatics – lymphangitis.
If grease is detected early, the symptoms can be treated fairly simply. However, the disease can become chronic, requiring treatment periodically for the rest of the horse´s life.

Watchfulness and carefulness are extremely important for detecting grease symptoms at an early stage. As the Shire has feather, the fingertips must serve as the ‘eyes’. Feel the pasterns through the feather every day. They should feel soft and silky at the skin surface. If not, apply a little greasy ointment and massage well. The feather should not be cut away as it helps to keep out the dirt. If grease is detected early it may be sufficient to rub in an oily healing ointment two-three times a day, or wash the area with diluted iodine solution or even mild soapy water.
Ointments that contain cortisone can help. If you suspect a bacterial infection you should contact your vet as a certain type of antibiotic ointment might be needed. A disinfectant compress is good if the skin is damp and festering, in which case it might better to apply an ointment that dries the skin, e.g. zinc salve. If it is a serious case then you might need to cut away the feather to make it easier to clean the area, but this is a last resort if you own a Shire!
If the situation is as above, then it is very important to keep the legs clean. It may be advisable to wash them in the evening. Brush off the worst of the mud as soon as the horse is stabled, dry the legs, and brush and groom again when the legs are completely dry. To make sure the legs are absolutely clean, wash them and blow the feather dry with a hair dryer.
Horse owners know lots of cures for grease, so ask others who have had the same problems and find out how they solved them.