Hi - I'm not sure if edema is an allergic symptom or not, but I have heard that psyllium has a high frequency of allergic reactions.
If you find it is not for you, you may want to consider a totally different type of product. I did take psyllium for years, but found that I had a much better cleanse with Oxypowder anyway. I found it far more effective. You can see a lot of posts about this on the Colon Cleanse board.