I can't answer your question about what it is, but I can add some insight on flea bits. For some reason my husband draws the flea, if they are present he gets bitten. I can state it is not because he is sweet. He walks through the grass barefoot and by the time he gets back he has flea bites. Once his mom had an unknown flea situation due to the family cat and he was not in the house 15 minutes before his ankles were covered with red bumps. Not one of the other people in the house had any bites, his mom was horrified and had the problem corrected almost immediately. The only thing I wonder about is the fact you were out on Sunday and it was Tuesday till you noticed any problem. That does not sound like a flea bit, they are like any other insect bite, there is not a lapse of hours or days before revealing themselves. All of these little annoying creatures like fleas, bees, ants, ticks, and spiders (just to name some common bugs) bite, leave saliva and junk in the bite and our skin rejects the entire process by turning red and irritated. The more we scratch the more we spread the junk. If I get bit by a mosquito around the eye area I swell up like a balloon. Last time was above my left brow, I was bit early evening, by the time I went to bed my eyebrow was almost laying on my cheek, if my eye would have been black and blue I would have looked like I was in a fight. Took three days for the swelling to go completely away. I have read the sun and insect bites are more pronounced with the TKI's, (I am not looking forward to mosquito season). I keep wondering because it is on your ankles and the area is itchy red spots if it is not some kind of insect bite, instead of the TKI issues. Did you try a cortisone or anti itch cream, how about Caladryl lotion, that works well also, I keep the clear the pink stuff gets on everything. If one of these things bring you comfort I am betting on insect bites, then you are left discovering what kind and where they attacked you. Good luck!