Thyroid autoantibodies can cause itching, although I'm not sure how, but I was tested for antibodies to thyroid for my itching. My was negative, as was all my allergy testing.
I'm glad your itching has stopped. I wish mine would. I'm having a whole slew of other symptoms, which I think point to lupus, as they are the same symptoms I had prior to transplant. Extreme fatigue, joint pain, muscle pain, all increased. My eyes are burning and very dry, my nose burns, I'm nauseous after I eat and have actually lost 10 pounds in the last couple of weeks. Headaches...the list goes on.
I'm very frustrated with it all. I'm taking 3 allergy medications, steroid eye drops and nasal spray, which does help some, but I'll flare and despite the medications, I'll feel miserable for a few days, come out of it, only to go back to miserable if I do too much. All I'm doing lately is sitting around and it's making me depressed.
At least the rash is cleared up, but if I scratch, it reappears. I see the immunologist in about 10 days, so hopefully he'll have suggestions on managing this better.