Acute otitis media
This type of infection is often caused by bacteria associated with a cold or sore throat, which can travel up the Eustachian tube, causing infection. The infection can cause pus and bleeding, and the eardrum may burst as a result of the pressure. In most cases, a burst eardrum heals by itself.

Chronic otitis media
If the eardrum does not heal completely, or if it has been punctured by a blow to the head, the ear becomes vulnerable to chronic otitis media. This type is not as painful as the acute type, but it can last for longer and the infection can occur over and over again. Chronic otitis media can also be caused by a condition called cholesteatoma, which causes an over-production of tissue in the middle ear.

Glue ear
This can develop if the Eustachian tube gets blocked. If this happens, the pressure inside the ear cannot be regulated. A sticky fluid builds up inside the middle ear and affects hearing.

Blockage of the Eustachian tube may be caused by an infection, an allergy, or by enlarged adenoids (cells at the back of the throat which help fight infections).

Children are particularly vulnerable to glue ear because they are less able than adults to fight off infections, and also because their Eustachian tubes are shorter, lie in a more horizontal position, and are more easily blocked. Children who get allergies and hay fever are more susceptible, too.

Acute otitis media

Symptoms of acute otitis media include:

• severe earache
• a feeling of fullness in the ear
• deafness
• ringing in the ear
• fever
• a discharge of blood and pus if the ear drum ruptures
• feeling generally unwell, with nausea, vomiting or diahorrea
• children tugging at the ear or having trouble swallowing their food

Chronic otitis media

The symptoms of chronic otitis media are much less severe than with acute otitis media. It is usually painless, but there is likely to be a discharge of thick, smelly pus, and hearing may be affected.

Glue ear

There are no obvious signs of glue ear. Children sometimes complain that their ear feels plugged up but the main symptom is deafness, which, in small children, is often mistaken for lack of attention.

To diagnose otitis media, the doctor may:

• look into the ears with an instrument called an otoscope
• take a sample of any discharge for laboratory analysis
• take a sample of blood for testing to confirm the presence of infection
• carry out some simple hearing tests
• request head X-rays or a CT scan to discover whether the infection has spread from the middle ear

Left untreated, acute and chronic otitis media can lead to deafness or other serious complications. Glue ear rarely causes long-term physical damage, but the temporary deafness can affect a child's educational and social development. For these reasons, it's important to see a doctor if you think your child has otitis media.

Acute otitis media is often given a chance to clear up on its own. If this does not happen, it may be treated with antibiotics. Sometimes, nasal drops or sprays are prescribed to help unblock the Eustachian tube. Eardrops or tablets may be prescribed for the pain.

If the eardrum is likely to burst, a specialist in ear, nose and throat problems may perform a procedure called a myringotomy. This involves making a tiny hole in the eardrum (under general anaesthetic) so the fluid can drain out. The eardrum should heal about a week after the infection has cleared.

Chronic otitis media may be treated with antibiotics to clear the infection. However, surgery provides a more permanent solution. An operation called a tympanoplasty can repair the perforated eardrum, as well as any damage done to the bones in the middle ear. Alternatively, if the condition is caused by cholesteatoma, the excess tissue can be surgically removed.

Glue ear may clear up without treatment, but may also be treated with antibiotics. When hearing loss is involved, some doctors recommend a tympanostomy - an operation in which a tiny hole is made in the eardrum and a tube called a grommet is inserted. This allows lets the ear drain continually, and usually restores hearing.

If a child does have a grommet, an earplug must be used when swimming to prevent bacteria entering the ear. He or she should also be examined regularly by a doctor. The grommet usually falls out after eight months to a year, and the hole usually closes within another eight to nine months.

Not all doctors recommend grommets. The risks include permanent damage to the middle ear or eardrum.

Good management of colds, flu and sore throats, and of hay fever and other allergies may help. There is some evidence that breastfeeding babies during their first three months, and that feeding babies in an upright position, decreases the risk of glue ear. Passive smoking and using a dummy have been shown to increase the risk.