Hi Tex, my dd's milk allergy was confirmed by skin tests at around 9 months, although we had taken her off cows milk completely, and I had also gone dairy free as I was breastfeeding. She had similar symptoms, no athsma or excema, but lots of tummy trouble, wind, constipation (for which she was initially prescribed lactulose, which is derived from cow's milk!) and reflux, it is amazing how much of an impact it has on your child when you stop the offending food. She is now 3, and tells me that her ears and tongue itch when she inadvertantly has dairy.
Seeing a dietitian will help, but TBH, unless they are specifically trained to deal with allergies, you'll kind of be on your own, knowing that your child can eat certain brands of fish finger is not going to make a massive difference to your life. You need a specific list of ingredients that are milk derivatives, and try and work out how to adapt recipes and come up with new ones. Would be happy to give ideas if you like.
You mention that your dd seems sensitive to a number of foods, and that rings a bell with me, as I was constantly thinking that my dd was allergic to allsorts, this is just my opinion, but I think that after the onslaught of reacting and having to deal with an allergen for so long, her body was sensitive to things, and I'm still much more careful about her diet re additives and coulourings than I think I would have been. Keep a food diary, and note any reactions, but don't be afraid to try things again. HTH, good luck with the testing, if you're unhappy with the results of the skin prick testing, you might be able to ask for blood testing, which is more accurate and sesitive, but if you're kind of already aware of the allergens involved due to the food diary etc, then it's more of a confirmation process rather than a dx IYKWIM.