Aloe vera, one of the best anti bacterial agent for urticaria

Condition analysis:
First of all, you need to start keeping a food journal and a symptom journal. Eliminating certain foods has helped you a bit, but you are clearly reacting to more foods. You may have to try the elimination diet. Google it-- you basically start with rice and work your way slowly to other foods. It's radical, or seems that way for a week or so, but your situation is becoming unbearable for you, so you need to treat it seriously.

Second, you probably have already done this, but research all the non-food things that can cause hives and itching. I have actually had hives from sun exposure, so just because it is rare, doesn't mean it isn't affecting you! When I was a avid runner in graduate school, I got hives on my legs whenever I ran in my running shorts on the Town Lake trail in Austin. It was a beautiful six mile loop along some river marshes and tributaries that I couldn't run in the summer because I couldn't run it in shorts!

Instructions:
Aloe Vera and Vitamin E oil:
Aloe Vera is one of the best anti bacterial agent and if you mix vitamin E oil in it then you will have a mixture that you can apply on the burns and red patches of your skin caused by urticaria and become relieved and soothed.

Nettle:
Over the centuries, researchers have found this herb to combat many skin disorders. It is also very effective for urticaria patients. Boil some nettle in water and drink this tea. In case you cannot find this herb then you can drink green tea, which is also anti oxidant and helps a lot in healing process.

Cayenne pepper:
Intake of cayenne pepper normally or in capsule will help in decreasing the swell ups and also fasten the curing procedure.