The etiology of ANCA-associated vasculitis is not fully understood and may be related to genetic, viral infections, and environmental factors. ANCA-associated vasculitis is a group of systemic small-vessel vasculitis characterized by the detection of ANCA in the blood serum, which mainly involves small blood vessels (small arteries, microarterioles, microvessels, and capillaries), but may also involve medium and small arteries. The etiology of ANCA-associated vasculitis is not fully understood, and some studies have found that its occurrence may be genetically related.ANCA-associated vasculitis has also been found to be associated with viral infections. When infected with cytomegalovirus, herpes simplex virus, and hepatitis B virus infection, these viruses may cause ANCA-associated vasculitis. In addition to genetic and viral infections, a variety of environmental factors may also cause ANCA-associated vasculitis, such as bacterial infections, silicone exposure, specific medications, drugs, etc. These causes can lead to immune dysfunction, which can contribute to the development of ANCA-associated vasculitis. The pathogenesis of ANCA-associated vasculitis is quite complicated, and patients are advised to consult with the rheumatology and immunology departments of regular hospitals in detail.