An itchy back - how to prevent it happening please.....

I frequently get a maddeningly itchy back.

In a hot shower, I scrub my back fairly lightly, pretty much every day with an old fashioned bristled bath-brush with a long handle. And shower gel or soap.

But every day, at some stage I'll get a maddening itch on my back! Sometimes I can reach to scratch it, sometimes there's someone around to scratch it for me, sometimes I can rub up against a doorpost like a kind of farm-animal!

But how can I prevent it happening in the first place? Moisturiser? Not easy to apply it to my own back.....any other suggestions pls......... gratefully received.