[CSF rhinorrhea is an important differential diagnosis for patients with long-lasting runny nose]

CSF rhinorrhea is a rare cause of runny nose that should be considered as a differential diagnosis when dealing with patients with long-lasting problems. Symptoms that should raise the suspicion of CSF rhinorrhea include long-lasting, unilateral, clear, watery discharge that does not respond to treatment with antihistamines, vasoconstrictors or nasal steroids. Beta-trace protein or beta-2 transferrin assay is the best laboratory test for diagnosing CSF rhinorrhea. Identified CSF rhinorrhea should prompt a referral to a neurosurgeon or to an ENT surgeon with special interest in the field.