How does vasculitis arise?
Many different insults may cause an identical inflammatory response within the blood vessel wall. This inflammation is thought to arise through one or more of three main mechanisms. • Direct injury to the vessel wall by bacteria or viruses • Indirect injury by activation of antibodies, which then generate inflammation within the vessel wall • Indirect injury through activation of complement. Complement refers to a group of proteins in the blood and tissue fluids that attack infection and foreign bodies and can damage the vessel wall. Vasculitis can be triggered by one or more factors. Bacterial, viral or other infection Vasculitis due to infection can occur through any of the above mechanisms. Treatment of the infection can clear the rash. Any virus can be implicated, particularly hepatitis B and C and haemorrhagic fever. Drugs Drugs are a common cause of vasculitis particularly when in combination with other precipitants such as infection, malignancy (cancer) or autoimmune disorders.
