Eustachian tube dysfunction (ETD) can cause dulled hearing. It is usually a temporary problem that lasts a week or so and most commonly occurs during and after a cold. There are various other causes and sometimes it lasts longer. Often, no treatment is needed but decongestants, antihistamines, or a steroid nasal spray sometimes help.
What is the Eustachian tube and what does it do?
The Eustachian tube is a narrow tube that connects the middle ear with the back of the nose. In adults it is about 3-4 cm long. The middle ear space behind the eardrum is normally filled with air. The air in the middle ear is constantly being absorbed by the cells that line the middle ear. So, fresh supplies of air are needed to get to the middle ear from time to time.
The Eustachian tube is normally closed but opens from time to time 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, enables the eardrum to work and vibrate properly, which is needed to hear properly.