frequent unexplained high fever

My grandaughter , age 4 has had a run of high fever, tiredness and no appetight every 3 weeks for the last 3 years. Th e fevers last about 3-4 days and range from 102-104 degrees. anyone have any idea what this could be? She has lost wieght and has no energy. Are there tests to help diagnose this problem.

[8yritch]

Hi,
  I have a 9 year old little girl who has been suffering with frequent high fevers (between 102-105.6) for years now.  They happen every month, recently becoming more frequent, at about every 2 weeks.  It always starts off the same, with a headache and fatigue.  By the next day the fevers start.  The higher her fever gets, the worse the headache, and sometimes she gets nausea and vomiting.  Sores in her mouth also happen frequently due to the fevers.   She loses her appetite and only drinks water, and will eat while the advil is working, however always very lightly.  She has underwent exhaustive testing, full blood work ups and cultures,  urine, x-ray's ECG's, HIV... never with any conclusive results.  Recently they have noted that her iron is low, so we are starting to supplement that, but it is extremely frustrating not to have a diagnosis.  (for everyone involved)  
  This has been happening as long as I can remember... since before her 2nd birthday is as far back as I can recall trying to bring down her fevers.  We've tried altering her diet, taking her off Dairy for years, tried eliminating wheat, nothing helps.  
  We are fortunate to have a pediatrician who is determined not to give up until we figure it out.  Her lymph node on the right side of her neck is swollen almost all the time, (larger when the fevers are happening) so it's been suggested that we may try biopsying that.  
  I'd also like to note that it is not contagious.  Everyone else in our family rarely gets fevers and we never reduce our contact with her when she is sick.  (even sharing water glasses) She's been around many people while fevered and no one else ever gets it.  
  I'm always thinking about symptoms that could be related.  She has dry, rough skin in patches on her legs, arms and torso.  She's always had it though, and no one has ever made any connections with that.  She also has quite extreme mood swings at times... but that could just be her :)
  Good luck with your quest for diagnosing your grand daughter.  It might be a long and difficult struggle, but please share your discoveries if you have any, and I will be sure to do the same.