Maybe have you previously endured a common cold virus? Perhaps did you get rid of the infection? Certainly you did! You cannot heal a runny nose itself, nevertheless your immune system normally creates immunity to a specific cold virus within a few weeks. That is called cured by your personal immunity!Adults have previously had a great deal of the rhinitis viruses. Adults have created immunity to the viruses they have had. So there are not as many cold viruses around for adults to become infected with. That is why parents just acquire a couple of runny noses per year whereas kids may get a dozen colds per year.