It has never truly gone away for me. That being said, the itch was absolutely terrible before I got on the meds, like, on a scale of 1-10, it was a burning 7 or 8, depending on the day. Now (on the big three), I have some days where I get zero scalp itching, then the occassional days with 5-15 minutes of 2/10ish itch. On the worse days, it is probably a dull but easily bearable type of 4/10 itchiness.
So as you see (in my case) - it is never nearly as bad as it was when I started balding, and sometimes it goes away completely for a bit. But it is still there. The best advice I can get is to not scratch your head. If you just man through it for a bit, it goes away (for me anyways). The times I've scratched my head for an instant relief - it has gone on for a longer time and I end up scratching pretty badly, possibly even resulting in some hair loss from the scratching itself in addition to the redness of the scalp.
I feel like my scalp is getting a bit better with time though, with me adding some nutrients to my regimen, changing up my non-Nizoral shampoo and also combing more often. (Keeps the scalp cleaner, no sebum build-up like I had when I didn't comb much if at all in my balder days).