The exact cause (or causes) of glue ear is unknown, but it seems to be due to a problem with a part of the body called the Eustachian tube.
The Eustachian tube
The Eustachian tube is a thin tube that runs from your middle ear to the back of your nose.
The Eustachian tube has two main functions, which are explained below.
- It ventilates your middle ear, helping to maintain a normal air pressure within the middle ear. Sudden changes in air pressure can be painful and, in some cases, can damage the ears. Changes in air pressure are responsible for the popping sensation that many people experience on an aeroplane.
- It helps to drain away mucus and other debris from the ear. The middle ear can often become clogged with mucus due to inflammation, infection or, in some cases, an allergic reaction.
With glue ear, the Eustachian tube seems to lose the ability to drain away the mucus. The mucus builds up inside the ear, which leads to glue ear. The reasons for this loss of function are still unclear, but some suggestions include:
- changes in air pressure inside the ear that lead to a blockage in the Eustachian tube
- inflammation of the Eustachian tube due to infection or irritants, such as cigarette smoke, which causes the tube to narrow
- gastric fluids from the stomach that leak up through the throat and into the Eustachian tube
- genetic mutations (altered genes) – some children may be born with certain genetic mutations, so their Eustachian tube does not develop properly
Risk factors
While it is not known exactly what causes glue ear, several factors have been identified as potentially being linked to an increased risk of children developing the condition.
These include:
- living in a house where the parents smoke
- not being breastfed
- having a brother or sister who also developed glue ear
- having a large number of brothers and sisters (this may be due to a higher risk of infection when there are several children in the house)
- having a cleft palate (a cleft palate is a type of birth defect where a child has a split in the roof of your mouth)
- having allergic rhinitis (an allergic condition that causes cold-like symptoms such as having a runny nose and sneezing)
- having Down’s syndrome (a genetic disorder that causes learning difficulties and disrupts physical development)
- having cystic fibrosis (a genetic condition that causes the lungs to get clogged up with thick, sticky mucus)
