it could be an allergy or bug bites,throw your mattress out and your quilt,change your washing powder see what happens
my friend was having same kind of itchy rash as if some sort of allergies or a mosquito bite, but after 2months we i also had the same then we discovered BED BUGS in our house . when we done with all treatment of bed bug the all allergies was gone all the itchy rash all that . so dont mind check if it is bed bug?
A couple questions: did the docs take cultures? What kind of detergent do you use? Do you have any allergies?