99 and 100 aren't really fever...have you had any temperatures higher than that? Any other symptoms such as night sweats or weight loss? I know many patients say that "Well that's a fever for me," but it doesn't really work that way. When we talk about fever of unknown origin, by definition it must be greater than or equal to 38.3C (that's about 101F), it must have gone on for more than 3 weeks and initial investigations have not proven any obvious source.
Infectious diseases physicians often see these types of cases in their clinic. You always want to rule out an occult infection (tuberculosis outside the lung, an intraabdominal abscess and endocarditis) and also an occult malignancy like lymphoma. Did you have any CT scans of your abdomen and/or chest?
Unfortunately, up to 30% of people who present with an FUO don't get a specific diagnosis; however, the nice thing about this is that they are the ones who tend to get better spontaneously without any treatment.
PS I should also mention that many docs forget to look in to their patients' mouths when they present with FUO. Have you had problems with your teeth? Have you gotten an echocardiogram to rule out endocarditis? (infection of a heart valve)
Last edited by harka; 11-10-2010 at 10:06 AM.