Southern Cross Medical Library

Southern Cross Medical Library

Middle ear infection is a bacterial or viral infection that may cause earache, temporary hearing loss, and fluid discharge.

Middle ear infections occur mainly in early childhood, although older children and adults also get these kinds of infection. It is estimated that one in four children will develop an acute ear infection before they turn 5 years of age. Children should always be taken to a doctor if they have earache.

What is middle ear infection?

The ear is made up of three different sections: the outer ear, the middle ear, and the inner ear. These parts all work together so you can hear and process sounds. The outer and middle ear are separated by the eardrum – a very thin piece of skin that vibrates when hit by sound waves.

This page deals with middle ear infection (otitis media), which is the infection / inflammation of the air-filled space behind the eardrum that contains the tiny vibrating bones of the ear. This space can become blocked and filled with mucus (a slippery fluid secretion), which can become infected, causing inflammation.

There are two types of middle ear infection:

  • An acute infection that starts suddenly and lasts for a short period of time; and
  • A chronic ear infection that does not get better or keeps coming back. Chronic ear infection can result in long-term damage to the ear.

Sometimes gel-like fluid will remain in the middle ear after an ear infection, causing "glue ear", a relatively common condition that is often undetected among New Zealand pre-schoolers. Glue ear can adversely affect hearing and may take several weeks to resolve.

Outer ear infection (otitis externa) is characteristically different to middle ear infection. This is a skin infection in the outer ear canal, which may start as an itch and develop into infection causing inflammation. Sometimes referred to as swimmer’s ear, this kind of infection can normally be treated effectively with ear drops from your doctor or pharmacist.


A middle ear infection often begins as a common cold, influenza (flu), sinusitis, or strep throat infection. The nose and throat are connected to the ear by the eustachian tubes. Bacteria or a virus enter the nose or throat and travel up the eustachian tubes to the middle ear.

The accumulation of fluid in a blocked eustachian tube may increase the pressure within the middle ear causing pain. Sometimes the pressure can cause part of the eardrum to tear (rupture).

Although the eardrum will repair itself, frequent rupture (which can occur with chronic ear infection) may result in the development of scar tissue on the eardrum and hearing loss. Middle ear infections are common in children because their eustachian tubes are narrow and easily blocked.

Risk factors

Factors that increase the likelihood of developing ear infections include:

  • Younger age (children aged 6 months to 2 years)
  • Group childcare
  • Bottle feeding infants while they are lying down
  • Seasonal factors (autumn and winter)
  • Poor air quality (exposure to tobacco smoke or high levels of air pollution).

Symptoms and diagnosis

Typical signs and symptoms of middle ear infection include:

  • A feeling of pressure or blockage in the ear
  • Earache - pain in the ear that is sharp, dull, or throbbing
  • Muffled hearing
  • Discharge from the ear, known as 'runny' ear
  • Ringing in the ears (tinnitus)
  • Fever of 38°C or higher
  • Headache
  • Irritability
  • Dizziness or loss of balance
  • Vomiting and diarrhoea.

Specific signs that your baby may have an ear infection include crying or grizzling more than usual, they keep touching their ear, and/or they have a discharge from the ear. An older child may show some of these signs or complain of having a sore ear.

Children with a suspected ear infection, or who have difficulty hearing, should see a doctor. Children with evidence of damage to the inside of the ear, hearing loss, or language learning delay are likely to be referred to an ear, nose, and throat (ENT) specialist (otolaryngologist).

To diagnose ear infection, a doctor will likely use an otoscope, which is a specialised instrument, with a light and magnifying glass, to look inside the ear to detect fluid behind the eardrum. A pneumatic otoscope is a special type of otoscope that allows the doctor to gently puff air against the eardrum. The puff of air should cause the eardrum to move. If the middle ear is filled with fluid, there will be little or no movement of the eardrum.

Note: earache is a common symptom of middle ear infection, but not all earaches are caused by a middle ear infection. A build-up of ear wax in the outer ear, or changes in altitude or air pressure, are examples of other causes of blockage or earache.


Ear infections usually clear up on their own, so treatment may begin with managing pain and close monitoring of the condition. However, ear infection in infants and severe cases of ear infection may require treatment with antibiotic medication.

Self-treatment (after having seen a doctor) may help to relieve symptoms, including:

  • Holding a moist warm face cloth or wheat bag against the infected ear
  • Taking medication for relief of pain or fever as directed by your doctor or pharmacist
  • Lying with the affected ear against your pillow, or sitting propped up in bed
  • Gently washing the outer ear with soap and a face cloth to remove any discharge
  • Keeping background noise in the home to a minimum.

You should never use cotton buds to clean your ears or your baby’s ears, or put anything into the ear that has not been prescribed by a doctor, as the eardrum is delicate and can be easily damaged.


The risk of middle ear infections in babies can be reduced by keeping rooms warm and dry, ensuring a smoke-free environment, and breast feeding for as long as possible (preferably longer than six months). If bottle-fed, babies should be held in an upright position while being fed. Showing older children how to blow their nose properly can also help prevent ear infection. Children's vaccinations should be kept up to date.

Taking steps to avoid catching a cold or flu will also reduce the risk of developing a middle ear infection. This can be achieved by washing hands frequently, not sharing eating and drinking utensils, covering the mouth when coughing or sneezing (using a disposable tissue or covering your mouth with the crook of your arm), and getting a seasonal flu vaccination.

The use of a nasal decongestant during a cold, influenza, or sinusitis, may also help to prevent an ear infection.

Further information

Ministry of Health

Healthline 0800 611 116

Royal New Zealand Plunket Society

PlunketLine 0800 933 922


Gribben B, et al. (2012). The incidence of acute otitis media in New Zealand children under five years of age in the primary care setting. J Prim Health Care. 2012;4(3):205-12.
Mayo Clinic (2019). Ear infection (middle ear) (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. [Accessed: 08/02/21]
Ministry of Health (2018). Earache (Web Page). Wellington: New Zealand Government Ministry of Health [Accessed: 08/02/21]
Ministry of Health (2016). Ear infections, earache and glue ear (Pamphlet). Wellington: New Zealand Government Ministry of Health.
O’Toole, M.T. (Ed.) (2017). Otitis media. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.
Waseem, M. (2020). Otitis media (Web Page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. [Accessed 08/02/21]

Reviewed: February 2021

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The purpose of the Southern Cross Medical Library is to provide information of a general nature to help you better understand certain medical conditions. Always seek specific medical advice for treatment appropriate to you. This information is not intended to relate specifically to insurance or healthcare services provided by Southern Cross.