A rash whch started under my arm, went down my arm, then up to the back f my neck, now it has spread to under my breast. I have a few lumps elsewhere on my body, none on my legs as yet. It starts by feeling very prickly and itchy and keeps spreading downwards. At first i thought thy were bites but keeps going down and becomes larger and spred out like hives . am trying antihistamine and cortisone cream. doesn t seem to be helping.