What Causes Itchiness All Over The Body While Having High Insulin Level?

I have PCOS, slight high blood pressure. My sugar is normal. But my insulin is slightly high. I would like to know why I have developed itchyness. In the groin area, my hands, under my breasts, and where my waitband sits below the stomach area and my neck and scalp. The itchyness has started since i changed my diet to a healthier eating plan. Breakfast gluten free bread toast with nuttelex and coffee, lunch a nutriblast with banana kale broccoli strawberries, dinner meat or fish with vegetables, snacks almonds or yoghurt. And i have noticed if i sway from that and have a piece of cake thr itchyness is so much worse. Could it be the sugar causing the itch or hormone level changes Im 44 yrs old. Thanks.