Food Allergies!?

A few months ago, Tayler broke out in hives all over her body that only lasted for a few minutes. When I took her to the doctor, they said it could be anything... food allergies, her body's reaction to a virus, her reaction to something she breathed in, etc. We thought it was ketchup but she hasn't had a problem with ketchup. When she eats, the area around her mouth usually gets red but we thought it was just her having sensitive skin. None of us (me, kyle or Colton) have food allergies so we didn't think that's what it could be. So, today the kids had chicken nuggest, grapes, carrots, cauliflower and ranch. This is not the first time Tayler has eaten ranch with her veggies. She usually gets red on her face when the ranch gets on it, just like with the ketchup. Today, I gave her light ranch instead of the regular ranch. During and after lunch, this is what she looked like...

(her face - everywhere the ranch touches, including her forehead, she breaks out.)

(left arm - the ranch did NOT get on her arm)

(right arm - this happened about 5 minutes after she was done and out of her chair; you can also see her little thumb all red)

So, I am thinking she may be allergic to ranch or something that is in it, especially the light ranch. She is going to the doctor tomorrow for vaccinations so I am going to see what she says and if they can do any tests.

When Tayler was about 2 weeks old, she developed an allergy to the milk protein in my breast milk. She eventually grew out of it. She drinks whole milk and doesn't have any problems with it, as well as yogurt and cheese, so I am wondering if there is a specific ingredient that she may be allergic to. For now I will rely on Benadryl and hope we can figure out what's causing her to break out!

update: I compared the ingredients in ketchup, ranch and light ranch. They all have dried onion. The light ranch also has onion puree and today when she had the light ranch, she broke out all over (in the pictures.) She also broke out when she had salsa, which usually has onions. So, I am thinking she may be allergic to onions....