Toddler keep having viral infection

Hate when i go doc they will just say viral infection. Mine says viral infection, went to another clinic got diagnosed with hfmd. Then another time say viral infection end up influenza A which was pretty serious. Do get it checked if they consistently get hight fever for more than 3 days, esp with cough and flu. Might be influenza. And yes! Fever always spike at night idkw. Dueing the day sometimes theyre active, at night fever will always spike. But pls bring to a&e if too high 39.8 and feed ibuprofen if above 38.5. Scared seizure.