I didn't read all the comments, so I don't know if this has been mentioned... but:
I don't have advice for the actual fevers but, since you son is having high fevers regularly I recommend you read up on febrile seizures. I'm not trying to add more stress and worry to your situation, but it should be something you are aware of if your child has recurring high fevers (like ours did). One day when our son was around a year old he had a fever of around 104.5 and he went into a seizure. It was terrifying. Again, I'm not bringing it up to scare you, but had I known what was going on I wouldn't have been so scared when it happened. I recommend that you know how to care for a baby during a seizure just in case. A little info on the subject will go a long way if it ever happens.
My son is 4yr son reaccuring fevers started in April and they have lasted for 7days. His fever ranges from 102-104 and the Dr says is virual and the fever has to run it's course. I am so sick of hearing this, I thought there was hope last month (May) Dr gave him antibiotic but took him off after Strp test came back negative. Now today he started his fever cycle again. He is seen at a military faciltiy and I am getting really frustrated. I am glad I am not crazy or being a over protective mom. I know something else has to be going on here it isn't normal for a child to have fevers every month let alone lasting more then 3 days. My plan is to sked his med appointment and if they say "virual" crap to me I will be asking for a referral to see another Dr outside of the military facitilty.
my 4 yr old daughter has the same thing. it started when she got a viral infection when she was 9 mos old and since then she gets a fever every 3 mos. it changed when she turned 2, it became every month. few months ago i took her to the e.r. due to 105.2 fever and stomach ache. they told me it was u.t.i. and she has high wbc due to infection then they send us home with antibiotics. her pedia said it was not documented as uti because the urine culture was mixed flora. she suggested renal sonogram and repeat urine culture. all results were normal. after that she had 3 episodes again, took her back to her pedia and she said it was viral. now her temp is 98.9 and i know it is starting again. ill take her to the e.r.. tom and will ask them about periodic fever and tonsils problems.
My son is the same way and I can't get answers either. It's always just a virus and I know it's not. It is something else and I can't seem to get the doctors to listen to me. His highest fever was 105.2 and I can tell when he gets sick because his breath smells like aerosol spray or something. They don't seem to care about his weird breath. He just turned 2 yesterday and he has had croup 10 times since birth and pneumonia 8 times. We moved out of our apartment because we thought something there might have been making him sick but it doesn't seem to be helping. He has a 5 year old sister and she is never sick.
We did end up seeing an ID Dr as well.They have been very helpful in letting us know what tests the Immuno should do as well.Have you seen an Immunologist yet.I think that may be a good place to start.
Does she get a sore throat with the fevers? If so ID can help you.Our son was dx with something called PFAPA. Unfortunately for us after we had his tonsils and adenoids out his fevers and infections still never stopped.
He is also being tested for Cystic Fibrosis.Our ped is having a sweat test done on him to rule it out.
Aslo have you been seen by GI to see if she has underlying reflux which could cause many infections such as sinus,ear etc.There are many different avenues you could look into.
Let me know if you have anymore questions please.
My daughter is 18 months old and we are having the same problem. She has fevers that range from 103-107.4 and we have also gotten the recurring "virus" of "fever of unknown origin" diagnosis. I took her to a children's urgent care and the dr. there recommended that she see an infectious disease specialist. I'm trying to work that out now. Please let me know if you make any progress with your child. I am also at the end of my rope!