my child has been dealing with a fever on and off for two weeks. she developed a rash all over with clusters on her arms and legs. we've been to emergency room twice. the fever goes away with ibuprofen but it comes back when that wears off. she's been tested for strep and pneumonia. both tests came back negative. the rash has gone away but the fever continues. she's had headaches and mild soreness in her knees.