Hi Barbara,
I have just come across your post. I had a Gastric Sleeve almost two years ago. I had no complications and my diet, although smaller quantities, has not changed in any way. I have suffered from chronic hives since the surgery and never had them at any time in my life previously. I'm going through hell. Every morning I wake up with them all over my body...feet, hands, face, hair...everywhere. They are huge, raised, red lumps that itch like nothing on earth. My eyes are red and swollen. I take antihistamines which eventually take them down 2-3 hours later. I'm clueless as to what is causing this. I am in misery every day. There are cases like ours online but no studies or conclusions.