Vasculitis is the inflammation and necrosis of vessel wall and may be a primary disease or secondary to another condition. At present, there is not an accurate classification; rather, classification depends on the changing nomenclature of these conditions and it is difficult to categorize some syndromes because they involve several vessel sizes. The most interesting type of vasculitis for the pediatrician is Kawasaki disease. New developments in this field are showing a relationship between this disease and superantigens. Some patients are resistant to high doses of intravenous gammaglobulin; in such cases, when some risk factors are present, some authors suggest the use of steroid pulse therapy. Inflammation of vessel walls results in occlusion of the lumen with necrosis; many other diseases have similar findings, such as infective endocarditis, Sneddon's syndrome, and others discussed here that should be included in the differential diagnosis.