Red, Blotchy, Itchy Skin, Hurts While Swallowing, Itchy Throat, Causes ?

I have red, blotchy and itchy skin. My throat also hurts something awful. It hurts to swallow anything, even saliva . I work with young children but I have never experienced this before. I had an itchy throat on Saturday morning and ended up throwing up water and then Sunday( yesterday) I noticed my face being blotchy. Now today I wake up and my face is still blotchy. I had a shower and now my chest and neck are also blotchy and very itchy too. What could this be?