What is your preferred management approach for scleroderma renal crisis in a patient with a history of anaphylaxis to ACE inhibitors?

The important thing is to lower the BP regardless of the how. ACE I were the first medication to show survival benefit in patients with scleroderma renal crisis so they have become the treatment mainstay. Time is kidney so the best treatment is to lower the BP with whatever BP lowering medication you have at your disposal.