Vasculitis is an autoimmune disease that effects the blood vessels. A low fat diet that is rich in fruits, vegetables and whole grains is typically the best diet for anyone, especially those with serious health conditions such vasculitis. I would talk to your doctor about any dietary recommendations or restrictions, especially if you are taking blood thinners or medications that can require special dietary needs. In rare instances, the National Institute of Health, have even tied certain foods or additives directly to cases of vasculitis. Although this is rare, it is a good idea to rule out if a food is actually causing or aggravating your condition. http://www.ncbi.nlm.nih.gov/pubmed/1505105 This condition is referred to as hypersensitive vasculitis when triggered by a food.