Why do we get Earache?

We are often asked why children (and occasionally adults) get earache. So, to answer demand, here is our guide to why ears ache...

First, a little detour into normal ear anatomy is required:

In the normal ear, the ear drum completely blocks the ear canal. Not even air can pass through it.

Behind the ear drum there is an air space (there must be air in order for the eardrum to flex as it is not possible to compress a liquid or a solid) in which are located the three ossicles.

The ossicles, from left to right the Malleus, Incus and Stapes are the smallest bones in the body and transmit the vibrations of sound in the air efficiently to the cochlea. The cochlea is a fluid-filled organ which converts sound into nerve impulses which then pass along the auditory nerve and are interpreted as hearing by the brain.

The air in the middle ear space is being absorbed all the time by the rich blood supply that surrounds it and must be replenished from the outside air. This occurs along the eustachian tube which runs from the middle ear to the back of the nose (right beside the adenoid glands). Every time we swallow, the eustachian tube opens, pulled upon by the muscles of the back of the throat, allowing the outside air to equalise the pressure in the middle ear cavity. This is usually accompanied by a gentle popping sound.

So, what goes wrong to cause earache?

If the eustachian tube becomes blocked (say by swelling of the tube or adenoids, or with mucus) the middle ear space is isolated from the outside air and a vacuum begins to form. This occurs quite quickly - just see how your ears feel if you don't swallow for a few minutes. The outside air begins to press upon the eardrum, stretching it in and preventing the ossicles from moving freely. This hurts a lot and reduces hearing. Eventually the eardrum is unable to move at all, a bit like the safety button on a jar of jam before it is first opened..

The eardrum, being flexible and stretchy does try to return to its proper position, and in doing so, applies suction to the blood vessels of the middle ear space, which leak fluid. This results in fluid filling the middle ear space (sometimes you can even see bubbles!).

The fluid secretion continues until the pressure in the middle ear is balanced by the pressure applied by the eardrum. In some cases this causes the eardrum to bulge and stretch and in others it does not. All of this is very painful, but when the pressure has equalised, the pain stops. The patient is left with an ear which works poorly until normal eustachian tube function is restored, usually within a few weeks.

Earache is often worsened by lying down. This is because the pressure in the veins of the ear is increased, causing a little more stretching of the ear structures. Even this soon passes.

Why does it affect children more than adults?

In children the eustachian tube is very small and in some cases, not fully developed. This means that only mild inflammation is required to cause a blockage. The adenoid glands are also relatively large and can contribute to blocking of the tube.

Not all children get earache and not all children who have congested ears will complain of symptoms. In a large study, over 85% of children had at least 2 weeks of congested ears before their second birthday.

Adults have much more space around their adenoid glands and have larger eustachian tubes. This leads to earache being only an occasional problem for most adults, often associated with swimming or flying though occasionally a really nasty cold will trigger the problem

How do I prevent earache?

There is little that can be done to prevent children catching the colds which cause earache (and trying to do so may even increase the risk of asthma).

Having the adenoid glands removed can be useful in severe cases and some children who have many problems benefit from grommets. Grommets are little tubes which are placed through the eardrum. These act like an artificial eustachian tube.

Otovent, a device which encourages high pressures in the nasal cavity has been shown to be of limited value in reducing earache symptoms. It is only really suitable for older children though who often have very few problems.

Vaccination against HIB and Pneumococcus has been shown to reduce earache. These are useful (and both are included in the NZ schedule) but cannot prevent the viral causes of earache.

There is no evidence to support the use of any herbal, natural or homoeopathic remedy in the prevention or treatment of earache. Decongestants, inhalers and sprays have no proven benefit either. Remember that 90% of earache will get better within 24 hours and 97.5% within 3 days whether it is treated or not.

What about bacteria?

Bacteria do occasionally colonise the nutrient rich fluid that fills the middle ear space. Sometimes they cause more pain and can cause more serious infections. It is important to have any child whose earache lasts more than 3 days seen by a doctor. Children under 2 should probably be seen after 24 hours of pain. Children with high temperatures or who seem unwell or who do not respond to simple painkillers should see a doctor sooner. If in doubt, check it out.

There is growing evidence that bacterial biofilms may have a role to play in earache.  These are clusters of bacteria protected by their own secretions.  It is hard for the body to attack these bacteria and hard for antibiotics to penetrate.  It is possible that some earache may be caused by bacterial biofilms obstructing the natural ear ventilation.

Recent studies have identified bacteria in most middle ear fluid.  The role of these bacteria is uncertain and we know from reliable studies that antibiotics do not seem to help earache so how significant this finding is remains to be seen.

My child gets earache a lot...

Some children suffer with earache more than others. Those who have more problems may benefit from grommets or other treatment. This is a complex field, though, as there is no hard and fast rule as to who needs treatment and who does not. This question is best answered during an appointment with the doctor.