Vasculitis is a systemic disease that mainly involves blood vessels throughout the body. The severity of vasculitis depends on the degree of systemic damage to the vasculitis, and compared to other rheumatic diseases, systemic vasculitis is supposed to be a more serious type of disease. However, with reasonable treatment, symptoms can also be relieved in the long term. The main clinical manifestations of vasculitis vary depending on the type of vessels involved, the site of onset, and the pathologic features. Most systemic vasculitis has an acute onset and more systemic damage, such as aortitis, which may involve the brain and cause cerebral hemorrhage and syncope. Nodular arteritis may involve internal organs, causing gastrointestinal bleeding or kidney infarction. Although most vasculitis manifests itself more severely, with reasonable treatment, some vasculitis is more stable and symptoms can be relieved. Of course there is a small percentage of systemic vasculitis that will be milder, such as leukoaraiosis, which may simply present as recurrent oral mucosal ulcers. As long as the systemic damage is mild, the presentation is often milder. In addition, vasculitis can be a monogenic primary disease for which no clear cause can be found, or it can be a clinical condition secondary to a disease such as systemic lupus erythematosus, rheumatoid arthritis, or malignancy. Therefore, treatment needs to first identify the cause of the disease. If the vasculitis is caused by allergies or connective tissue diseases, the primary disease can be better controlled and the symptoms of vasculitis can be relieved at the same time. However, if the primary cause is a malignant tumor, the symptoms of vasculitis secondary to the tumor are relatively severe and difficult to relieve because the condition itself is difficult to control. Therefore, whether vasculitis is serious or not cannot be generalized. It has to be judged specifically according to the degree of systemic damage and the primary disease.