What causes an ear infection?
An ear infection is often the result of bacteria, fungi or a virus causing problems in any of the three parts that make up your ear. The three parts of your ear include the outer ear, the middle ear and the inner ear.
Your outer ear includes the pinna (visible outer ear) and the canal (called the external auditory canal) that leads to the eardrum
Your middle ear is behind the eardrum and contains three tiny bones (the ossicles: malleus, incus and stapes) that amplify sound.
Your inner ear is where sounds are translated to electrical impulses by the cochlea and sent to the brain.
There are many causes of ear infection. Some of the contributing risk factors are:
- upper respiratory tract infections (a cold for example);
- smaller than average Eustachian tubes, such as in young children;
- swimming in polluted waters;
- failing to dry the outer ear properly after swimming or bathing; and
- excessive cleaning of the ears with cotton buds or other foreign objects.
The symptoms depend on the type of infection and where it occurs in the ear, but may include:
- mild deafness
- ear discharge
- loss of appetite
- blisters on the outer ear or along the ear canal
- noises in the ear, such as buzzing or humming
- vertigo (loss of balance)
5 Common types of ear infection
There are many types of ear infection, some more exotic than others. Most are caused by bacterial or fungal infection. The following are 5 that you might come across.
Otitis media is a generic term used to describe a number middle ear infections. The more prevalent conditions include acute otitis media, otitis media with effusion and chronic suppurative otitis media.
Otitis media is common in babies and young children and becomes less common in children over the age of six. Otitis media is the leading condition for antibiotic prescribing and surgery in young children.
Children with otitis media will usually have symptoms related to:
- fever and/or pain (acute otitis media)
- difficulty hearing (otitis media with effusion)
- ear discharge (acute otitis media with perforation or chronic suppurative otitis media).
Acute Otitis Media
Acute otitis media (AOM) is a bacterial or viral infection of the middle ear that progresses rapidly. It is a common problem in early childhood. The middle ear will show signs and symptoms of acute inflammation and effusion, usually within 48 hours after symptoms begin.
The symptoms of otitis media are earache, discharge from the ear, ear popping, ear fullness, hearing loss, fever and dizziness.
A baby or young child who has AOM may tug on the ear, cry or fuss more than usual, lose his or her appetite, and have trouble sleeping.
Visible with a microscope, a bulging tympanic membrane is typical in a case of AOM.
Otitis Media With Effusion
Otitis media with effusion (OME), also called glue ear, is characterised by fluid in the middle ear without signs or symptoms of inflammation. OME can occur just prior to or persist after an infection for a few days or up to many weeks. Children are more likely to experience OME due to the small size and shape of their Eustachian tube relative to adults.
About 90% of children have OME at some stage, most often between the ages of 6 months to 4 years.
OME isn’t an ear infection, but they can be related. For example, an ear infection can affect how well fluid flows through the middle ear. Your ear may retain fluid even after an ear infection is resolved. A blocked Eustachian tube and excess fluid provides the ideal environment for bacteria to flourish. Flourishing bacteria may then lead to an ear infection.
Otitis externa, also called swimmers ear is an infection of the outer ear. Often the result of water getting trapped in your ear, followed by the growth of bacteria or fungal organisms. It commonly occurs during the summer months when people swim more frequently and their ears stay warm and moist.
Possible causes of otitis externa may include:
- swimming in water that contains bacteria;
- scratching the inside of your ear; or
- getting something stuck in your ear.
Otitis externa is also more common in tropical environments, where it is often more difficult to keep your outer ear dry.
The usual signs that you may have otitis externa are itchiness in the ear, hearing loss, ear pain, and having yellow or yellow-green, smelly pus drain from the ear.
This type of ear infection is typically treated with antibiotic ear drops. The ears should also be kept dry during the treatment of this ear infection. Microsuction may help to clear the ear canal, making it easier to administer ear drops, soothe the irritation and relieve the blocked feeling.
Mastoiditis is more common in children, but it can affect adults as well. It is caused by a middle ear infection that has been left untreated. The infection can spread from your middle ear, invading the mastoid air cells in the temporal bone of your skull.
Symptoms include swelling, tenderness and redness around the temporal bone. Fever, ear pain and discharge are also possible.
Many vital structures pass through the mastoid, so if an infection spreads outside of the mastoid bone serious complications can occur. The infection cannot be treated at home and should always be assessed by a health care professional.