Perchance have you heretofore suffered through a common cold virus? Perhaps did you get rid of the cold? Obviously you did! You can not heal a runny nose directly, but your body typically creates resistance to a certain cold virus within a few weeks. That is called cured by your very own immune response!
Parents have currently had a lot of the rhinitis viruses. Adults have actually established resistance to the viruses they have had. Therefore there are not so many runny nose viruses remaining for adults to catch. That is why adults only acquire a few runny noses per year whereas youngsters may get 10-12 runny noses per year.
http://claytonrmtu050.theburnward.com/hpv-cures-itself