Itchy Skin

I have a very sensitive skin. Whenever I go out in the sun for too long, I get hot flushes and my cheeks start burning. I was suggested to use sunscreen cream every four hours. But my skin doesn't tolerate any chemical ingredient of these creams. The so called herbal creams have also proved useless for me. When ever I am in stress or excited, I get the same hot flushes. Can any one suggest a remedy?
For too long, I used Eumosone, but It always gives me only a temporary relief. I have heard that corticosteroids interfere with your hormonal imbalance. So I stopped using Eumosone cream.
Which is the best medicine to treat itchy skin?