Sarcoids - sarcoid skin lumps - are the most common type of skin tumour in horses. They are not cancerous but do cause a lot of problems in many horses. No one knows what causes them but it may be that they are started off by fly-bites and that there is so form of viral involvement when they are first formed. It is certainly true that weakness in the immune system makes Sarcoids worse. You may find that they increase in size after vaccination or other shocks to the system. Quite often the reason a given horse has Sarcoids is some underlying deficiency or concurrent disease.

Horse Sarcoids take many forms: flat bumpy areas of skin like Ringworm, crusty lumps like warts or smooth nodular growths. They are most commonly found underneath the belly, inside the thighs, behind the elbows and under the girth and also on the head and neck.

One of Sarcoids most worrying characteristics is the way that they spread out and grow back after being surgically removed.