Suggest Treatment For Rashes On The Legs And Ankles

I was out in 90 degree weather for a few hours. I had used 30 sunscreen. I have patches of a rash only on my legs from my ankles to the bottom of where my shorts were. The raised bumps are random patches. Mostly on the front of my legs but a few on the back. The rash did come up about 20 minutes after eating ice cream that had coconut shavings cocoa and caramel in it. Not sure if it is food related? My skin on my legs felt tight, burned, I started shivering, had a headache, itched. I took ibuprofen and later benedryl & drank lots of water. The itching lessened, but my ankles and legs have swollen. I flew home on a plane today. just took loratadine. I am not sure if hives or sun poisoning or new food allergy but would guess flying did not help my issue