Since December Every Few Weeks I've Been Breaking Out In

Since December every few weeks I've been breaking out in an itchy rash, went to hospital was told i had scabies, did the treatment and all else they told me to do. No one else i know had this, really don't think that was the problem, any ideas on what could be going on? I have very sensitive skin and do not use different products of anything at anytime, I'm going crazy with this!