What Causes Intermittent Itching And Raised Skin?

Hi, Over the last few months on and off I ve gotten some kind of skin reaction. Not sure to what, haven t changed products. I have gone to a normal doctor, dermatologist & allergist all cannot tell me what it is. I would gladly provide pictures. The spots only come onto my arms and sometimes my face. Usually in the same spots. They start off looking like a misquito bite raised and once I notice I start to itch which then causes them to become red. They do not stay raised although throughout the day they become itchy on and off. I ve gotten off of all meds so it isn t those. My last idea would be my puppy who is almost a year old. I ve had her for a year come July and these started around November so the allergist ruled it out, although on my test it said I was allergic (I don t show symptoms). Not sure what to do or where to go from here.