What does the Eustachian tube do?
The Eustachian tube is normally closed but opens when we swallow, yawn or chew. This allows air to flow into the middle ear and any mucus to flow out. This keeps the air pressure equal either side of the eardrum. Having equal air pressure on each side of the eardrum and the middle ear free of mucus, helps the eardrum to vibrate. This vibration is needed for us to hear properly.
How do we hear?
Sound waves hit the eardrum. Vibrations of the eardrum pass on to tiny bones (the ossicles) in the middle ear. These bones transmit the vibrations to the cochlea in the inner ear. Sound signals are sent from the cochlea to the ear nerve and then on to the brain.
How do things go wrong?
If the tube is blocked or does not open properly, air can't get into the middle ear. Therefore, the air pressure on the outer side of the eardrum becomes greater than the air pressure in the middle ear. This pushes the eardrum inwards. The eardrum becomes tense and does not vibrate so well when hit by sound waves.
What causes short-term Eustachian tube dysfunction?
- By far the most common cause is a simple cold: a blocked, runny nose and lots of production of mucus will partially block the Eustachian tube for a week or two.
- This causes the typical muffled hearing and a feeling of popping in your ears when you yawn or swallow.
- This is not usually serious and clears up by itself in a few weeks.
- Although it can be a bit sore when the ear 'pops' occasionally, this short-term problem shouldn't be very painful.
- This is a common situation in children, who often have a mild loss of hearing when they have a cold.
- Once the cold has gone the hearing returns to normal within a week or two.
What causes long-term Eustachian tube dysfunction?
- In adults, the symptoms can go on for longer. This usually has a different cause to a common cold.
- Allergies that affect the nose, such as persistent rhinitis and hay fever, can cause extra mucus and inflammation in and around the Eustachian tube and lead to having symptoms for several months.
- Smoking can make the tiny hairs that line the Eustachian tube stop working. In general, anyone who smokes and who has symptoms of long-term (chronic) Eustachian tube dysfunction will be advised to stop smoking.
- Anything that causes a blockage to the Eustachian tube can cause muffled hearing - for example, enlarged adenoids in children.
- Rarely, a tumour behind the eardrum or at the back of the nose (the nasopharynx) can mimic the symptoms of Eustachian tube dysfunction. But these types of tumours are very uncommon.
Did you find this information useful?
- Norman G, Llewellyn A, Harden M, et al; Systematic review of the limited evidence base for treatments of Eustachian tube dysfunction: a health technology assessment. Clin Otolaryngol. 2014 Feb 39(1):6-21. doi: 10.1111/coa.12220.
- Balloon dilatation of the Eustachian tube; NICE Interventional Procedure Guideline, November 2011
- McDonald MH, Hoffman MR, Gentry LR, et al; New insights into mechanism of Eustachian tube ventilation based on cine computed tomography images. Eur Arch Otorhinolaryngol. 2011 Nov 27.
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