 [ Symptoms ] i have recently had breast surgery removal of calcium deposits with cancer cells [ Disease ] unfortunately without the ability to actually see this skin eruption that you are describing it would be very difficult if not impossible to blindly offer an accurate diagnosis a diagnosis is really essential when it comes to treatment knowing your medical history will also help solve this mystery rash based solely on your description this could be an allergic reaction perhaps urticaria hives hives are intensely itchy comes on suddenly and if the allergen is still in your midst it can continue to persistspread regardless of the cause which can be very challenging to find the itchiness can be treated with an antihistamine like diphenhydramine benadryl or other over the counter medications in this class seeing a medical provider is important since many things can mimic hives