My 7 Year Old Daughter Has Very High Fevers Of

My 7 year old daughter has very high fevers of 104-105 degrees plus.She was diagnosed with periodic fever syndrome at the age of 1.5. When she was 4 the fevers stopped for 2 yrs. they started up again over the last year and a half. Tested for viruses but negative. Allergies might be a possibility i was told or tonsils and adnoids...