Nose and sinus
CSF rhinorrhoea
CSF rhinorrhoea is a leak of the clear fluid that cushions the brain and spinal cord, escaping into the nose through a small gap in the thin bone that normally separates the two. Because this gap can also let infection travel the other way, a suspected leak is always assessed properly rather than treated as a simple runny nose.
ENT care in Bandra, MumbaiAbout Dr Adip Shetty
On this page
What causes a CSF leak?
Most leaks follow a head injury or surgery on the sinuses or skull base. A smaller number happen without any injury — a spontaneous leak — often linked to raised pressure around the brain, which is more common in people who are overweight. Rarely, a leak follows erosion of the skull base by a growth.
How does it present?
The main sign is a clear, watery discharge from one side of the nose, sometimes with a salty taste, that often worsens on bending forward, straining or coughing. It can look like a cold or allergy, but a discharge that is one-sided, constant and water-like is treated differently.
How it is checked
A sample of the fluid can be tested for beta-2 transferrin, a protein found only in CSF, to confirm the diagnosis. A CT scan of the skull base looks for the site of the gap, and an MRI or a dye test during endoscopy is sometimes added to pinpoint it precisely.
Treatment
Many leaks that follow an injury settle with rest, avoiding straining and keeping the head elevated, often within one to two weeks. A leak that persists, or a spontaneous one, usually needs an endoscopic repair through the nose, placing a graft over the gap. Any underlying cause of raised pressure around the brain is addressed too, to reduce the chance of it returning.
When to seek help sooner
Take a clear, watery, one-sided nasal discharge seriously, especially after a head injury or sinus surgery, or if it comes with fever, a stiff neck, severe headache or confusion, as these can signal meningitis. This needs emergency assessment, not a routine clinic visit.
A note on your care
“A constant, watery drip from one side of the nose is never just allergy until it has been checked. Tell us if it started after a head injury or any nose or sinus surgery.”
A little more clarity
Common questions
Is a CSF leak dangerous?
The main danger is infection travelling into the fluid around the brain, which can cause meningitis. This is why a suspected leak is assessed and treated rather than watched indefinitely.
Can a CSF leak be mistaken for allergies?
Yes. A one-sided, constant, watery drip differs from the two-sided, itchy discharge typical of allergic rhinitis, and should be tested rather than treated as allergy alone.
Will I need surgery for a CSF leak?
Not always. Many leaks that follow an injury settle with simple measures. A persistent or spontaneous leak more often needs an endoscopic repair through the nose.
Can a CSF leak come back after repair?
It can, particularly if an underlying cause, such as raised pressure around the brain, is not also addressed.
Sources and review
Updated . General information to help you prepare for a consultation.
Clinically reviewed by Dr Adip Shetty on .