Melody, good morning. Has a dermatologist done a skin biopsy? FYI, even REALLY good dermies very often can't know what a rash is merely by looking at it. I once read that there are something like 17,000+ named skin conditions.
Another possible specialty: A small group of dermatologists are credentialed in BOTH dermatology AND pathology, meaning they're dermies who do THEIR OWN labwork. They're called "dermatopathologists". They probably gravitate to teaching hospitals.
My rashes turned out to be SCLE (subacute cutaneous lupus erythematosus), the "annular" form (meaning targetlike). There's a second SCLE rash called papulosquamous, which resembles psoriasis (but isn't). People with these rashes very often (not always) test positive for anti-Ro, the one I mentioned earlier that's seen in both lupus and Sjogren's.
In mature form, my lesions were targetlike, appearing on photo-exposed skin on upper arms and back. They didn't itch, hurt, or bleed. Lesions actually began as red raised papules that resembled mosquito bites (but no itch). Next, the papules expanded into perfect circles with clear centers. As the lesions aged, the circles expanded even further, lost perfect circularity, and merged into one another. Last step: they disappeared. Next step: A NEW BATCH! By the 8th year of this nonsense, I had rashes of all ages simultaneously.
I saw many local dermies, all incapable of Dx'ing my rash or of even ordering the most appropriate tests. In contrast, the teaching hospital drs. I finally saw recognized my rash in maybe 1 second flat, but of course ordered new tests (deep-punch biopsy with stain tests) for scientific proof.
So that's why I'm always curious about rashes: I understand how frustrated one becomes when answers aren't forthcoming, esp. when your rash feels correlated to your OTHER symptoms. I hope you keep posting here. Sending best wishes, Vee