GREASY HEEL (sometimes referred to as mud fever) is a skin condition correctly known as pastern dermatitis. It can be caused by a variety of bacteria, which thrive in muddy, wet conditions. It can also be brought on by compromised immune systems and humid conditions when mycotoxins are present in grazing grasses. These same concerns can also present as RAINSCALD over your horses upper body.
Greasy heel and Rainscald are not to be ignored, these can be a sign of nutritional or environmental concerns and also require a topical management plan to be in place.