It can cause a painful skin rash, I don't know if this is what you're seeing or actual welts. If you've been going to the same doctor for 10 years it may be time for a second opinion. Below is an excellent site to answer all your questions. Take care.
Thankyou so much for your reply! june 6th I will be going in for an endoscopy. I have been diagnosed with Multiple Chemical Sensitity disorder. I hope some of those symptoms will subside if this is the cause.