Is having temp that goes to 99.9 every night briefly normal? starts at 97.7 in morning, spikes to 99.9 by night for few months. i have swollen neck nodes, but pet and bloodwork show nothing except high esr and crp. is this temp fluctuation normal?

FUO: This qualifies as a fever of unknown origin and in such cases I recommend consulting a specialist in infectious diseases for a workup which is best done in the hospital for a few days. Negative PET scan is strong evidence against lymphoma. Epstein-Barr virus mononucleosis can be a rare cause of a FUO. Lymph node biopsy may be part of the testing along with appropriate cultures,mono test.