**8. Treatment of localized vasculitis**

#### **8.1. Trimethoprim/sulfamethoxazole (T/S)**

There have been case reports and case series of patients with AAV limited to the upper and/or lower respiratory tract treated with T/S for induction of remission with a good outcome [72]. A study of 72patients withGPAlookedatthe role ofT/S forinductionofremissioninthe localized stage, and maintenance of remission in the generalized stage [73]. Nineteen patients with localized disease received T/S (2×960 mg/day) with 58% achieving complete or partial remis‐ sion for a median of 43 months. Patients with generalized disease in remission did poorly with T/S, with 42% of those treated with T/S alone relapsing after a median of 13 months compared to a relapse rate of 29% at a median of 23 months in the patients not receiving T/S.

T/S was found to be superior to placebo in maintaining remission in a prospective, placebo controlled study of 81 patients with GPA, 41 of whom received T/S after induction of remission of generalized disease [74]. At 24 months of follow-up 82% of patients in the T/S group were still in remission, as compared to only 60% in the placebo group, with a relative risk of relapse of 0.40 (95%CI 0.17 to 0.98). This reduction was especially evident with respect to relapses involving the upper airways.

Therefore, T/S can be considered for the induction of remission of localized GPA but patients should be monitored carefully for signs of progression to systemic disease. The efficacy of maintenance of remission in generalized disease is controversial and currently not the recommended standard of practice.
