Swelling Hands at near end of 12.5 training run - new to this forum (Read 502 times)

I felt fine otherwise - besides the usual - a little hot - a little tired - but nothing unusual. All of a sudden, my left hand feels really strange - I look down and my palm is very red - my hand is swollen quite a bit. I check my right hand and it too is swollen with a red palm. This has never happened to me. I used only water for this run - with shot bloks. When I started my run it was about 73 degrees - probably high 70s to 80 when finished - steady rolling hills - which i have run many times.. Any ideas on what may havew cause this to happen? I have a low grade anemia and very mild lupus. Otherwise, I am very healthy. Thanks.