Vasculitis Classification and Treatment

Classification of Vasculitis

The American College of Rheumatology recommends classifying vasculitis according to vessel size (large, medium, small) as per the 2012 Chapel Hill Consensus Conference nomenclature, with treatment tailored to the specific type and severity of vasculitis to reduce morbidity and mortality 1, 2, 3
Large vessel vasculitis affects the aorta and its major branches, and includes conditions such as giant cell arteritis (GCA) and Takayasu arteritis (TAK), typically affecting patients over 50 years old 4
Medium vessel vasculitis affects main visceral arteries and initial branches, and includes conditions such as polyarteritis nodosa (PAN) 5, 6, 7
Small vessel vasculitis affects intraparenchymal vessels, and includes conditions such as ANCA-associated vasculitis, including granulomatosis with polyangiitis (GPA), and immune complex small vessel vasculitis, including cryoglobulinemic vasculitis and IgA vasculitis (Henoch-Schönlein purpura) 1, 7, 8, 9

The European League Against Rheumatism recommends treatment goals of inducing remission, preventing relapse, and minimizing treatment toxicity, with severity assessment evaluating the extent of organ involvement to determine treatment intensity 5, 6, 7
For ANCA-associated vasculitis, treatment options include rituximab, cyclophosphamide, and high-dose corticosteroids, with maintenance therapy typically continuing for 18-24 months 5, 6, 8, 9, 10
For large vessel vasculitis, initial treatment includes high-dose corticosteroids, with steroid-sparing agents such as tocilizumab, methotrexate, or leflunomide considered for long-term management 4
For medium vessel vasculitis, treatment options include cyclophosphamide plus corticosteroids, with plasma exchange considered for severe disease 5, 7
Infection prophylaxis with trimethoprim-sulfamethoxazole is recommended during immunosuppressive therapy, with regular monitoring of disease activity, treatment toxicity, and infection 5, 6, 7
Pregnancy requires modification of the treatment regimen to avoid teratogenic medications 5

Diagnostic challenges require a multidisciplinary approach, with biopsy recommended when feasible but not always essential, and consideration of comorbidities such as cardiovascular risk factors, osteoporosis prevention, and infection risk 10, 9, 7
A multidisciplinary approach is recommended for diagnostic evaluation, especially for complex vasculitides, with involvement of specialists based on organ involvement and regular assessment of disease activity using validated tools 10, 9, 5, 7

LVV primarily involves the aorta and its major branches, but may also extend to medium‑ and small‑vessel territories. 11
Giant cell arteritis (GCA) occurs in patients > 50 years, targeting supra‑aortic vessels and extracranial carotid branches such as the superficial temporal artery. 11
Takayasu arteritis predominantly affects young women (≤ 40 years) with preferential involvement of the aorta. 11

Variable‑vessel vasculitis is defined by the absence of a predominant vessel‑size involvement, encompassing diseases that do not fit the large, medium, or small categories. 11

Because tissue biopsy of large or medium vessels is often impractical, imaging modalities are essential for the diagnosis of LVV and MVV. 11
The classification framework acknowledges overlap: LVV can involve medium‑ and small‑vessel territories, and variable‑vessel vasculitis specifically addresses conditions without a dominant vessel‑size pattern. 11