What type of mysterious rash is this?

Hello, recently my 3 year old son and i have come down with a weird rash.  It is kind of small, red bumpy but is extremely itchy.  I've considered maybe it is scabies, however not everybody in my family that lives with me has it, just the two of us.  It gets worse at night yes, but the rash only shows up where you have itched it.  I have taken my self and my son to many doctors, no one seems to have any idea what it is.  Anyone else on here have a rash like this or could soothe my mind and tell me what kind of rash this is?  Thanks