Why did I get vasculitis?

Unclear. Vasculitis is one of those enigmas as to why however it may be autoimmune you should discuss this with your doctor.
Origin of Vasculitis. Vasculitis can be caused by many types of underlying illnesses or be the primary illness. Scientists are not exactly sure why some patients develop this type of inflammation and others do not. The best we can do is tell the patient that it is a combination of underlying disease, genetics, and other ill-defined factors (nutrition, infections, etc).