You might be in the one percent of the population that has celiac disease or dermititis herpetiformis or both. I will add a bunch of websites for you to look at.
The first thing you should do is get a doctor to test you for celiac disease and dermititis herpetiformis which are both gluten intolerance conditions. Celiac disease affects the small intestine and can cause any number of symptoms including yours. Dermititis herpetiformis causes skin problems similar to eczema. The tests will start with blood work and then possibly an endoscopic exam of your small intestine(not a very difficult thing to go through) and also skin biopsies.
After you get tested and it turned out positive, the treatment will be a gluten free diet which eliminates all wheat, barley and rye from your diet and some people are sensitive to oats also.
If the tests are negative or inconclusive, then go on a 2-3 month trial gluten free diet to see if your symptoms go away. This will eliminate the possibility that you are non celiac gluten intolerant or allergic to wheat or gluten that didn't show up in testing. It is important to get the testing done before you stop eating gluten or you could get false negatives.
I had most of your symptoms for a long time and found out when I was 50 that I had celiac disease and within 3 months of going gluten free, I was able to stop my claritin, Advair, Albuterol, Medrol and it seems like one other. Anyway it was wonderful and well worth not eating gluten containing foods.
The dairy issue may resolve itself when you go gluten free since celiac disease seems to affect the parts of your small intestine that digest lactose. After you have healed, you may find yourself tolerating dairy again. In the meantime, limit your lactose intake or take a pill with meals called Lactaid. You can get it at a drug store without a prescription.
This is a lot of info but feel to contact me through here and good luck.
http://www.glutenfreeliving.com/ingredient.php(really good explanation of ingredients)