I had severe itchies too, though no rash. I used a menthol-based moisturiser, cool showers and cool cloths (I had damp face washers in the freezer at one point and I had scratch marks all over me from itching in my sleep and gave myself quite a few nasty wounds.

I think mine was a reaction to chlorine, because when I stopped swimming the itching stopped within about 2 weeks. Chlorine is usually not an issue at all, never has been. But that was my best guess as to what was setting it off.

I hope you find the cause, or a safe, reliable treatment. I totally get that itchiness can be torture. xo