Should you start taking allopurinol during gout attack?

No. Allopurinol shouldn't be started(or changed at all) during a gout flare. It should be started after a flare resolves.
NO !! Wait until attack has subsided and slowly add Allopurinol to treatment.This drug mobilizes uric acid (so the kidneys can excrete it) and can bring on or worsen an attack.