Skin rash when i'm wet?

every time i shower or get wet either by rain or beach, i get something that looks like mosquito bites. ever since i was a little girl. the rash last about and hour. it itches a lot, but i try not to scratch myself. i have gone to a lot of dermatologists, but they can't tell what can it be. i have normal skin, i don't use parfumes or dyes on the clothes, and everything is hypoallergenic. it is the water, obviously, because i get it everytime i get wet. any ideas what can it be?|||I've got the solution for you,don't get wet.