Unexplained fever

What are the different reasons for an unexplained fever in a 25 year old?

I have been diagnosis with unexplained fevers by my gp. I have had all the tests they have and all were negative. I get these fevers on a weekly/monthly.

My 5yr old child having unexplained fever in the fast 1week(102deg), not continuously once in a while.My paediatrician not able find the cause.Any test?

I've had a unexplained fever for a week. I had a copper IUD put in a month ago. I went to see the midwife that put it in and she thinks the fever is from a virus, but gave me a zpack anyways. I'm on day 4. Still no other symptoms other than the fever and

My daughter has had unexplained fever for 4 nights now. She ended antiboitcs for sinus/ear infection over a week ago. not contagious?

I have been tired, hand and feet burning.I can't take any one touching me . Bruises on my body easy.I throw up all the time, unexplained fevers?

I had an abdominal ct-scan for unexplained fever. They actually did 2 scans - one with iodine contrast and one without. Was it really necessary to do 2 scans, and hence double my radiation dose?

Hx of crohns, kidney failure, enlarged liver-14cm, skin issues, ^ in alt,ast,crp, extreme fatigue for 10yrs and unexplained fevers. maybe lupus?

Unexplained recurring fever with soar throat that goes away instantly with plaquenil (hydroxychloroquine). Ana crp was high now normal, ebv cmv b19 igg. Do i need igm test?

On remicade & advair. Can oral thrush (canidida) get into lungs from an infection on tongue & throat? Have unexplained high fever also now levaquin (levofloxacin)