I get itchy sites occasionally. For me, I do think,it's to do with the hot weather or getting hot.
I used to,get them more on my tummy so I presume it's to do with the senditvity of the skin too. I don't use my tummy any more and they have reduced a lot.
What I did is resist touching them if they were itchy; if they were really itchy, I moved my site. I let my skin cool down after a shower before inserting a cannula, and if I remove one and see any kind of rash, I bathe it with tepid water, pat it dry and, if needed, sometimes take an antihistamine. Usually they ease quickly then.
What sets are you using?