Ear infections

The ear is made up of three parts. The outer ear includes the part you can see and the canal that leads to the eardrum. The middle ear is separated from the outer ear by the eardrum and contains tiny bones that amplify sound. The inner ear is where sounds are translated to electrical impulses and sent to the brain.

Any of these three parts can become infected by bacteria, fungi or viruses. Children are particularly prone to middle ear infections (otitis media). It is estimated that around four out of five children will experience a middle ear infection at least once.

Symptoms of ear infections

The symptoms of an ear infection depend on the type, but may include:

• earache
• mild deafness or the sensation that sound is muffled
• ear discharge
• fever
• headache
• loss of appetite
• itchiness of the outer ear
• blisters on the outer ear or along the ear canal
• noises in the ear – such as buzzing or humming
• vertigo (loss of balance).

The function of the Eustachian tube

The ear is connected to the back of the nose via the Eustachian tube. This tube equalises air pressure inside the ear, and funnels secretions from the middle ear into the throat. The walls of the Eustachian tube lie flat against each other to prevent the migration of bacteria or other germs into the ear from the nose and throat.

Whenever we swallow, a small muscle flexes and opens the tube, allowing air pressure equalisation and the drainage of secretions. If the Eustachian tube is blocked, secretions and associated bacteria build up inside the middle ear. This can cause ear infections, mild deafness and an increased likelihood of a ruptured eardrum.

Causes of ear infections

Some of the many causes of ear infection and contributing risk factors include:

• upper respiratory tract infections
• sudden changes in air pressure – such as during airline travel
• smaller than average Eustachian tubes, or a blocked Eustachian tube
• cleft palate
• young age – babies and children are more prone to ear infections
• swimming in polluted water
• failing to dry the outer ear properly after swimming or bathing
• overzealous cleaning of the ears, which can scratch the delicate tissues.

Types of ear infections

Ear infections are diagnosed by physical examination and laboratory analysis of pus or discharge. In some cases, CT scans may also be taken.

Types of ear infection include:

• otitis externa
• otitis media – acute or chronic
• serous otitis media
• infectious myringitis
• acute mastoiditis
• vestibular neuronitis
• herpes zoster of the ear.

Otitis externa

Otitis externa is an infection or inflammation of the ear canal between the eardrum and the outer ear. It can be triggered by exposure to dirty water or by mechanical damage due to overzealous cleaning. The infectious agent can be either fungal or bacterial.

Treatment options include:

• professional cleaning of the ear canal, although syringing the ear should usually be avoided
• eardrops containing antibiotics and steroids, if the infection is bacterial in origin
• oral antibiotics
• ear drops containing antifungal medications and steroids, if the infection is fungal in origin
• pain-relieving medications
• keeping ears dry.

Otitis media

Otitis media is an infection of the middle ear, which can be either acute or chronic. Children are most commonly affected by acute otitis media because it is caused by colds and blocked Eustachian tubes – both typical ailments of childhood. The infectious agent can be either viral or bacterial, with research suggesting that viruses are responsible for most cases.

Sometimes the eardrum will burst, leading to pus in the ear canal, but usually the eardrum will heal up again by itself. Treatment options include:

• pain-relieving medications
• antibiotics – if the infection is bacterial in origin
• eardrops – if there is pus in the ear canal.

Frequent bouts of acute otitis media or one lingering attack can lead to chronic otitis media. Without medical intervention, the chronic infection can burst the eardrum or damage the delicate structures within the middle ear.

Other possible complications of untreated chronic otitis media include meningitis, infection of the balance organs within the ear (labyrinthitis), sensorineural deafness (permanent hearing loss) and paralysis of the face.

Treatment options include:

• thorough cleaning of the ear and use of topical antibiotic drops (with or without steroids)
• medication to treat the infection
• surgical repair of the perforated eardrum
• prevention strategies to reduce the risk of another infection.

Serous otitis media

Serous otitis media is known as glue ear. Children aged between six months and two years of age are most vulnerable to this type of ear infection. Glue ear commonly develops after a middle ear infection, and is characterised by the build-up of fluid and pus within the middle ear. Treatment options include antibiotics.

If antibiotics fail, or if the child is plagued by repeated attacks of glue ear, surgery to insert small drainage tubes (grommets) may be needed.

Infectious myringitis

Infectious myringitis is inflammation of the eardrum, caused by infection from either viruses or bacteria. The eardrum responds to the inflammation by forming small blisters. This can be quite painful. If fever is present, the infectious agent is almost certainly bacterial.

Treatment options include:

• antibiotics
• pain-relieving medications
• professional rupturing of the blisters

Acute mastoiditis

The bone that can be felt immediately behind the ear is called the mastoid. Acute mastoiditis is infection of this bone, caused by prior acute otitis media. The symptoms include reddened and swollen skin over the mastoid, fever, discharge from the ear and intense pain.

This is a serious condition. Untreated, acute mastoiditis can lead to deafness, blood poisoning, meningitis and paralysis of the face. Treatment options include:

• intravenous antibiotics
• surgical drainage of the infected bone.

Vestibular neuronitis

The inner ear contains the organs of balance – the vestibular system. It includes three fluid-filled loops (semi-circular canals) which respond to the rotation of the head. Near the semicircular canals are the utricle and saccule, which detect gravity and back-and-forth motion. When the head is moved, signals from these organs are sent via the vestibular nerve to the brain where it is processed

Vestibular neuronitis is inflammation of the vestibular nerve, probably caused by a viral infection. The main symptom is sudden and dramatic vertigo, which may be accompanied by nausea and vomiting. The eyes may also involuntarily flutter towards the affected side of the head.

Treatment options for vestibular neuronitis include:

• medications, including antihistamines
• anti-nausea medications
• vestibular physiotherapy – to help your brain to compensate or retrain.

Herpes zoster of the ear

Sound is sent as electrical impulses to the brain via the cochlear nerve. Herpes zoster of the ear is an infection of this auditory nerve by the herpes zoster virus. Symptoms include ear pain, vertigo, and small blisters on the outer ear and ear canal and perhaps on the face and neck.

The main nerve that services the facial muscles may also become infected, leading to swelling and partial paralysis. Treatment options include:

• antiviral medications such as steroids and acyclovir
• pain-relieving medications.

Where to get help

• Your GP (doctor)
• Pharmacist
• Audiologist
• Ear, Nose and Throat Specialist
• Royal Victorian Eye and Ear Hospital