6 month old appears allergic to food

[Mooshkelini]

My daughter is six months old, exclusively breastfed.  I have been trying to introduce new foods, she has gotten hives from every item I have tried to introduce.  So far I have given her the following:  Enfamil formula, rice cereal, oat cereal, pears, peas, carrots and sweet potatoes.  With all foods mentioned, she developed severe hives within a ten minute time frame, with the exception of sweet potatoes which I tried today and it took two hours for her to get hives.  I have waited until her hives disappear, usually giving her Benadryl, and waited two days before giving her a new food (though not every time), but she consistently gets hives.  They always coincide with her having eaten.  I tried a glass bowl and metal spoon as opposed to plastic, she still got hives.  We are not using new soap, we have always had a dog, and the timing is just too coincidental (at least I think so) for it to be anything else besides food.  

Her doctor says it could be months before she can get into a specialist.  He also provided no suggestions other than to give her a few days between reactions and then try another food.  I am really scared there is something majorly wrong with her, as I have also read that allergic reactions usually only happen on second exposure to food, whereas hers are now occurring on the first exposure to a food.  And how could she possibly be allergic to everything?  She otherwise appears healthy, happy, is gaining weight etc..  

Any information you could give me would be appreciated, I'm very worried about my daughter.