Eczema Treatment Care

Im not sure if you can have an allergy to food and the only side effect is sneezing? Eating certain foods make me sneeze lots (no not pepper or spices, I think its bread but im not sure) but its wierd because I dont get itchy or swollen or anything just some foods make me sneeze. But also I have contact dermatitis (if i said it right) since I was young. It means that if I am slapped or hit, or get any form of strong abbrasion/force against any skin on my body, the skin gets very red quickly and the main area of impact gets raised and white like a welt. A doctor told me this could either be very sensitive skin or a food allergy. Like, to give an example. If my back feels itchy, and I scratch it for say 2 seconds. Then it gets even more itchy and i scratch a couple more times, and then I can usually feel that my back feels all bumpy and I look in a mirror, and there are raised nailmarks everywhere I have scratched making a big jagged pattern on my back, and i am not scratching excessively hard or anything. When I get an itch, it does not go away unless I just plain ignore it for a very long time, it will keep getting itchier and itcher and spread if i itch it, im always like this. I dont know much about food allergies or skin conditions so if you know about either please leave a reply. Thanks