Dear "kayakchick",
We have not heard back from you after our comment, so here is our answer based on information you initially provided.
There are, at least, several diseases as differential diagnoses including Granuloma annulare, Sarcoidosis, Tinea corporis, Subacute cutaneous lupus erythematosus, Erythema marginatum, Erythema migrans.
Therefore, certain diagnostic tools are recommended such as skin biopsy, skin culture (to exclude fungal infection), serology test for Borrelia burgdorferi, CBC, SE & CRP, just to name a few.
Thank you for your question.
Wishing You Optimal Health,
Dr. Jasmina Jankicevic
Welcome to the Dermatology Expert Forum!
Before we approach you with the answer, could you please, tell us what diagnostic tools (such as biopsy, skin culture, etc.) were utilized by your doctor(s) in past, and what were the results? Also, what treatment was applied? Any success with it?
Thank you,
Dr. Jasmina Jankicevic