The Washington Post published a story on January 19, 2010 entitled "Doctors changed diagnosis after woman said allergies weren't causing runny nose." In this story, the patient's runny nose from only one side was actually due to a CSF leak (cerebrospinal fluid leakage) and puts her at major risk for meningitis. Unfortunately for this particular patient, the hole through which this fluid was coming out from also had some brain tissue. She required major surgery in order to correct this problem.
An interesting trivia related to CSF leaks is that actor George Clooney suffered one after a blow to the head while filming a torture scene in the 2005 movie "Syriana".
The take-home message is that not all runny noses are due to allergies, especially if it is continuous and only occurs on one side.
Read the story here.
Image taken from wikipedia.
