Treatment for Small Vessel Vasculitis

Disease Classification and Initial Assessment

The European League Against Rheumatism recommends that small vessel vasculitis should be categorized according to severity to guide appropriate treatment decisions: localized, early systemic, generalized, severe, or refractory 3, 4
ANCA-associated vasculitis (AAV) includes granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) 2
Disease severity assessment should include evaluation of organ involvement, particularly renal function and pulmonary status 2

The American College of Rheumatology recommends first-line therapy with high-dose glucocorticoids (prednisolone 1 mg/kg/day, maximum 60 mg/day) combined with either cyclophosphamide (oral 2 mg/kg/day, maximum 200 mg/day or IV pulsed) or rituximab (375 mg/m² weekly for 4 weeks) for severe/generalized disease 3, 4
Initial high-dose glucocorticoids should be maintained for 1 month, then tapered gradually to 15 mg/day or less during the first 3 months 3

The European Renal Association recommends that after achieving remission, transition to maintenance therapy with rituximab (using either the MAINRITSAN scheme: 500 mg at remission and at months 6, 12, and 18; or the RITAZAREM scheme: 1000 mg at remission and months 4, 8, 12, and 16) 1
The American College of Rheumatology recommends maintenance therapy with azathioprine (1.5-2 mg/kg/day) for 18-24 months, then decrease to 1 mg/kg/day until 4 years after diagnosis 1
Glucocorticoids should be continued at 5-7.5 mg/day for 2 years and then slowly reduced by 1 mg every 2 months 1

For refractory disease, the European League Against Rheumatism recommends considering increasing glucocorticoid dose (IV or oral) 2
For relapsing disease, reinduction therapy is recommended, preferably with rituximab 2

The American College of Rheumatology recommends prophylaxis against Pneumocystis jiroveci with trimethoprim/sulfamethoxazole (800/160 mg on alternate days or 400/80 mg daily) for all patients on cyclophosphamide 3
Patients receiving cyclophosphamide should be given Mesna to prevent hemorrhagic cystitis 3
Regular monitoring of blood counts, renal function, and urinalysis is essential 5
Bone protection therapy should be provided according to local guidelines for patients on long-term glucocorticoids 3