Hello Welcome to Healthcare Magic ,
i.e running nose , is usually due to upper respiratory tract
infection(URTI). URTI is most commonly caused by viruses , so just needs symptomatic management i.e crocin
drops for fever and some antihistaminics for cold. It usually subsides in a week .
In case symptoms persist or worsen beyond 2 days of onset or child becomes drowsy , not taking orally adequately , then there might be a bacterial infection for which you need to add on an antibiotic.
Hope i was helpfull....