What Causes Severe Itchy Bouts Of Skin?

Over the past year I was suffering from very itchy bouts of skin but with no significant signs of rash or bumps but over the last few months i have developed some rashes on my legs and arms. In February I suffered with swollen lymph nodes and I took my anti-biotics to get rid of that, then 21/2 weeks ago I suffered a bout of kidney stones. I was given injections for the pain and nausea and I was given an anti-biotic thereafter to clear up any infection. ever since the rashes have become very significat, especially at night, they develop into red lumps with blisters and leave very small scabs behind. the itching is almost burning and it spreads from the whole length of both arms to my hands and fingers. it is a very intense itching. over the past week I have also suffered with pain throughout my legs, feet and hands. especially later at night from 9.30pm onwards. the next morning I wake up and the rash is still visible but not nearly as inflamed. tonight it will flame up again.. can you please tell me what you might think this may be.