How do you approach the treatment of biopsy proven ABRA (amyloid beta related angiitis)?  

I start with a prednisone taper, 60 mg daily to start, taper over a few weeks. If symptoms or scan findings worsen, I would add an immunosuppressive agent such as azathioprine. Howard Kirshner MD

Agree with using prednisone for a few weeks and consider immunosuppressants if incomplete response to prednisone.