hi! according to one reliable source (www.emedicine.com)
, those who suffer from chronic atopic dermatitis have an increased sensitivity in general, and the most common causes of reactions with food are "peanuts, eggs, milk, soya, fish, and seafood."
my guess at the reason - milk contains many proteins and compounds that are normal to baby cows, but foreign to our immune system. because they are regarded as intruders, the immune system can go a little haywire and it can cause some local and systemic reactions, like you described.
you also have to keep in mind any new things you might be in contact with in general, from foods to clothing to personal products or shampoo or something like that. we are in contact with so many potential allergens every day that it can be hard to isolate one cause. but, try very carefully to think of ANYthing new you have been in contact with.
i wouldn't ever recommend tanning. one of my professors said tanning beds should be banned because of the ridiculously increased chances of skin cancer. i would also see a doctor, if at all possible, as it may actually be some sort of dermatitis infection that could be treated.
hope this helps!