I get itchy rashes that have pricking needles sensation and my heart beats very fast.They start in smaller size but later increase into a big size.I also feel breathlessness and my lips get swollen and my face and eyes swell.I get them mostly at nights and they come all over my body even in my head and are more in number on my legs.I feel very weak.After the itching decreases rashes leave a brown mark on my skin.please help.I am suffering this from last 4months.No one knows what it is.