External Ear Infection (Otitis Externa)

Otitis externa is a type of external ear infection, which is commonly known as “swimmer’s ear”.

The ear is divided into three parts: the outer ear (the pinna and external ear canal), middle ear (behind the ear drum), and inner ear (cochlea). Infections of the outer and middle ear are much more common than inner ear infections.

External Ear Infection (Otitis Externa)

An infection affecting the external ear canal is called otitis externa, commonly known as “swimmer’s ear”. Anyone can get otitis externa.

Symptoms of External Ear Infections

an itchy and/or painful ear with foul-smelling fluid discharge from the ear
hearing is often affected, and you may complain of your ears being blocked
the skin of the external ear will be red and swollen, and extremely sensitive to touch

Preventing External Ear Infections

The ear has a self-cleansing mechanism, and clearing of earwax with cotton tips or any tools is unnecessary. Earwax also has antibacterial properties that help to prevent ear infection.

If you swim regularly, it is important to make sure the ears are dried after a swim. Turning the head and gently pulling the ear in different directions can help drain water out of the ear.

Gentle use of cotton tips may be necessary but it is not advisable to vigorously clean the ear. Earplugs can be used to prevent water from getting into the external ear canal.

You can also prevent water from entering the ear canal in the shower by plugging the outside ear with a piece of cotton wool that is slightly soaked with baby oil.

What Causes External Ear Infections? 

The skin of the ear canal is normally protected by a waxy, water-resistant coating.

Bacteria living on the surface of the skin can cause otitis externa when there is a break in the skin’s barrier. Trauma to the skin of the ear canal from cotton tips or fingernails can result in a break in the barrier. Someone who swims frequently is also predisposed to external ear infection. Prolonged exposure to moisture results in the water-resistant coating and skin becoming soft, allowing bacteria to infect the skin.

High humidity in tropical countries, like Singapore, ups the risk for external ear infections.

Diabetics are at higher risk due to poor immunity. They are also more prone to an aggressive form of infection called malignant otitis externa, in which the infection involves the skull bone.

Diagnosis of Otitis Externa

Otitis externa can be diagnosed based on the patient’s history and/or a physical exam. Cultures of the ear fluid or swabs of the ear may be necessary to identify the specific bacteria and the antibiotics that are active against it.

Occasionally, when the offending agent is a fungus, the infection is called otomycosis. Spores and hyphae (an element of fungus) can be seen in the external ear canal.

How to Treat External Ear Infections 

External ear infections can be treated by your family doctor with antibiotic ear drops. Occasionally, an ear toilet procedure by a specialist ear, nose and throat (ENT) surgeon is necessary. The ENT surgeon may insert an ear wick into the ear to allow the topical antibiotics to reach the deeper part of the ear canal. Some prescription drops may contain topical steroids which can help to rapidly reduce pain and swelling in the ear. Sometimes, oral pain medicines are necessary.

In patients with diabetes mellitus, intravenous antibiotics may be necessary for the treatment of malignant otitis externa.

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