L.P.
Long sustaining runny nose weather from allergies or weather can very quickly and easily become infected. If the discharge has color it means infection. In a very young child infection can spread rapidly. Even in adults an untreated sinus infection can spread upward to the brain. By all means if the doctor prescribed meds for the runny nose I would give it as directed and finish all meds. This can also spread down to the lungs. Once the infection is in the body it is opertunistic and will travel any open path.