What Is Causing Mosquito Bite Like Patches All Over My Body?

Hi i have been very upset because i have been getting some mosquito bite type bloches on my skin and i mean all over sometimes even my eye lids are swollen or parts of my face i have been to the hospital but no one seems to know whats wrong with me. They have told me its an allergy but they still cant figure out where its coming from. Can you help me out to try to figure this out its ruining my life.