Otitis externa

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at June 19, 2016
StartDiseasesOtitis externa

Otitis externa is a common ear infection that occurs in the ear canal. The condition is also known as swimmer's ear because it is common to individuals who swim regularly. In most cases swimmer's ear is caused by fungi and bacteria. Otitis externa commonly affects adolescents. 


Definition & Facts

Otitis externa can be acute or chronic. Acute otitis externa is caused by pathogens, whereas allergies and other health conditions cause chronic otitis. Wearing hearing aids, inserting cotton swabs into the ears, and swimming are all risk factors for otitis externa.

In very rare situations, otitis externa can become life-threatening, which is known as malignant otitis externa or necrotizing otitis externa. In malignant otitis externa, the patient experiences minor symptoms of otitis externa for several months, accompanied by some pain and drainage. The infection spreads into all the tissues close to the canal, causing damage to several nerves. In some cases, malignant otitis externa causes life-threatening conditions such as meningitis, brain infection, and even brain abscess

Symptoms & Complaints

When a person has otitis externa, the first symptom they get is itching in their ear canal. After some time, the ear starts to get extremely painful. Some patients will also experience a lot of pain if the external part of the ear is touched or pressed. This happens because the skin around the ear canal is attached to the covering of the underlying bone directly.

Sometimes, the canal might get swollen, making hearing difficult. Some individuals get red swollen canals while others can get greenish yellow pus. If the infection is severe, some patients might get fevers. In most cases, this happens because the auricle, which is the part of the ear that is visible, is infected as well. The auricle will appear red and swollen when infected.


While experts say that the most common cause of otitis externa is bacteria, fungi and viruses can also cause otitis externa. Fungi that can be responsible for the condition include candida and aspergillus. Herpes virus hominis and varicella zoster virus are two viruses that have been linked to otitis externa.

Swimmer's ear is very common during the summer months in most places. During this time, many individuals go swimming in lakes and pools. When the ear canal is exposed to moisture from the water frequently, an individual can lose their cerumen which is the technical term for earwax. Cerumen protects the delicate skin that is found in the ear canal. Without the protection, moisture is easily retained in the ear canal, and some irritation starts. When the cerumen is lost, the ear canal loses its acidity, giving harmful bacteria an opportunity to multiply. 

Using cotton swabs to clean one's ear canals can also cause otitis externa. When cleaning the ear, the cerumen is pushed from its place into the ear canal. This exposes the ear canal to infections. The ear canal has a unique mechanism of working and cleaning. All the accumulations of the debris and cerumen should come out of the ear by themselves. Placing sharp items into the ear can also damage the ear canal, making it more prone to infections such as swimmer's ear.

Individuals suffering from diabetes are at a higher risk of developing malignant otitis externa. People with weakened immune systems are also prone to the infection. The bacterium that is usually responsible for malignant otitis externa is known as Pseudomonas aeruginosa.

Diagnosis & Tests

If the otitis externa is not complicated, diagnosis is not difficult. Pain in the ear that is worsened by a simple touch at the auricle is enough to diagnose otitis externa. To rule out any other infections, the doctor examines the ear canal. If there is some redness and swelling, it is likely swimmer's ear.

It is important for the doctor to understand the real cause of the condition. This can be done by gently swabbing the ear canal to take a sample. The sample will be used to determine the type of organism causing the infection. The organisms will be cultured in a laboratory and viewed under a microscope to identify the causative organism.

When malignant otitis externa is suspected, the doctor will request a computed tomography (CT) scan. An MRI scan can also be carried out to diagnose the condition. These scans will help the doctor to determine how the infection has spread to the patient's tissue and bones.

If the infection is severe, a simple swab from the external ear canal is not able to determine the cause of the infection. The doctor will recommend a biopsy. The MRI or CT scan will guide the doctor in deciding the area that is most affected. The biopsy is carried out on that site. 

Treatment & Therapy

If the condition is not severe and its cause is bacterial, it can be treated by the use of antibiotics. The medication should be applied directly to the skin around the ear canal. Apart from topical antibiotics, the patient may be prescribed corticosteroids. These medications play a major role in reducing the inflammation and swelling inside the canal. 

Some doctors will prefer to insert a cotton wick inside the ear canal and allow it remain there for a day. The antibiotics and the rest of the medications are applied in the wick directly several times a day. The wick should remain saturated continuously throughout the day. When the wick is removed, the patients can then apply the medications directly into the ear canal several times a day.

When the infection is serious, the antibiotics will be given through an IV. In some cases, the CT scan might reveal that the infection has spread extensively. In these cases, the antibiotics will be given for several weeks to ensure that the infection clears completely. In the early stages of malignant otitis externa, the IV medications can typically be substituted with oral antibiotics after two weeks. 

Prevention & Prophylaxis

Preventing swimmer's ear is not difficult and requires keeping the ears dry at all times. Every time a person goes to swim, they should prepare a mixture of alcohol and acetic acid. After swimming, they should put several drops of the mixture into the ear canal to ensure that it dries completely. 

It is also possible to prevent malignant otitis externa through early diagnosis. If symptoms of drainage or pain from the ear canal arise, visit the doctor immediately. All people who are at a higher risk of getting the infection should also be extremely careful. If a person's immune system is not strong or they have diabetes, they should report any symptoms to their doctor as soon as they notice them.