Cotton rich, lace-free, seam free blah blah !
Don't go crazy with the ordering, try one and see.....lol
If there are times you can go without a bra then do it, I know those times might be few and far between. If you need to wear your usual bra then you can also trying putting two or three sheets of nice soft tissue round the area (not too thick!). I don't mean loo roll or kitchen roll, but those lovely soft ones that you get in tiny handbag plastic packs. Put the bra on, lift the fabric in the area where its itching, slot in tissues (halved if needed) and keep the sheets nice and flat so that they cover the part of your itching skin. I found, that this seemed to help somehow as the bra rubbed on the slidey tissue not the skin ?! Worth a try ?