I completely understand the need for distraction having symtoms like yours. Strangely for me about a year before I got GD my body experience similar all over the body skin sensations without a rash. My skin would itch, sting and zap from the inside out. It's hard for doctors to understand if they can't see any symptoms. I would get relief from a powerful corticosteroid shot, Kenalog-40, Medicare covers this. These symtoms would abate for about 9 months then begin slowly. My dermatologist did want to give me this shot more then once a year. This shot did had side effects- massive hair thinning starting about 2 months after the shot, but now I'm not getting them my hair is back to normal. It also caused face redness for a few months after getting the shot. This shot did nothing for my GD when that developed. Yet at least my misery with GD was specific to the rash areas.
What stopped these sensations, which were particuarly intense at night when our histamines are higher in the evening, was giving up processed sugar. This was the most challenging dietary sacrifice I've ever tried, yet I succeeded. Read The Yeast Connecton Handbook, by William Crooke, MD. His theory is that the waste from the yeast living in our guts and passes though the intestines and into the bloodstream. It's causing a number of diseases, including eczema. I followed his initial detox plan for 3 months diligently. He only asks for a 2 month detox, but I was so much better after 2 months I kept it up for 3. This detox is rough. Now I follow a version of his lifestyle diet, which is no processed sugar for life, his lifestyle diet limits natural sugars and gluten, yet I slowly added these back into my diet and eat all of these foods I want now and still have none of my previous all over the body skin sensations which made me so miserable, unable to sleep and brought me to the point of suicide. I got though my detox and gladly give up processed sugar because my pain motivated me. If you try this, I can give tips on how I got though sugar withdrawal, I want to add I never had been overweith and probably ate less processed sugar than most.

Please tell me what testing your dermatologish has performed.
GD biopsy?
5 Day Extended Patch Test for Allergic Contact Dermatitis (ACD)?
Not all derms are licensed for this specific Patch Test, it's costly too, around $1,500 yet Medicare covers it. I was ignorant and for a decade when I first got eczema of the hands (which turned out to be ACD) I accepted what my dermatologist told me- that I had eczema (she didn't say what type) and told me to stop washing my hands so much and gave me topical steroids. I was a fool. She was never licensed for this tesing. I moved and went to another dermatolgist and his only treament was steroids. Once again I was ignorant. He left the area and I went to a new derm that gave this test. The internet was getting underway and I obsessively began educating myself.
If your dermatologist says he can't help you don't do what I did and accept it for 10 years!!! Find a new dermatologist and keep blogging with other with the same symtoms.

Unfortunately this disease is a mystery. Not everything works for everyone. My GD is disappearing. Here is what I take: apple cider vinegar, curcumin, and now liquid Coq 10. I have no idea if the Coq 10 has had any effect, but talking the liquid coincides with the lessening of the itching. Have you tried light therapy?