Non-specific viral syndromes are usually just that, a viral syndrome but, be cautious as a number of more serious ailments can present similarly. This includes tick borne illnesses, acute HIV and carbon monoxide
Doxycycline is safe in kids. The dental staining seen with tetracycline is specific to that drug, not the class. If doxy is the best drug for the disease, use it.
Lots of meds can lead to a myasthenia gravis exacerbation. Carefully review meds before prescribing for interactions