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Otitis externa is an ear infection of the outer ear- Otitis Externa

The ear infection varies upon its localization in the ear. Here we would discuss all you need to know about otitis externa.

What is the external ear?

The ear has a division in three portions, external, middle, and inner ear. In this article, we are only going to focus on the outer ear delimitation and structures. The external ear includes the auricle or pinna (both are medical terms and are correct), and the external auditory canal or just ear canal. The most superficial portion of the tympanic membrane or ear drum (see image 1) is also part of the outer ear, while the inner portion of the membrane is part of the middle ear. This membrane starts the division between both pieces.

The auricle has many other recognized structures with over-technical names that you would not need to know to understand this infection. What you need to remember are the core structures as the auricle, external ear canal, and the outer portion of the tympanic membrane.

(IMAGE 1) BruceBlaus / CC BY-SA (

What is otitis externa?

Otitis externa is an inflammation of the external portion of the ear. The ear infection is the primary cause of this, mostly by infective bacteria, but fungi are also common. However, other diseases may cause inflammation in the outer ear without any infection. The outer ear structures which could be affected include the external ear canal and the auricle, and it can affect each one of them separately or simultaneously. It would depend on the microorganism, underlying condition, and length of the infection, which is going to be the medical management of the otitis externa because it has a wide array of possible causes and outcomes.

Otitis externa is the same as the swimmer’s ear?

Yes, the swimmer’s ear is infectious external otitis. The name is used because of the close relationship of this infection with aquatic activities. Therefore, utilizing both terms, swimmer’s ear and a bacterial otitis externa interchangeably, are all right.

This association exists because of the water that remains in the ear canal after being underwater. Predispose the ear environment for the growth of harmful bacteria that lately will cause an infection.

However, it is essential to highlight that swimmer’s ear only refers to an ear infection by bacteria. At the same time, otitis externa can happen because of another microorganism different from bacteria or an inflammatory condition. So please do not get caught with these tricky terms.

Who is at risk of getting ear infections?

Patients with previous episodes of otitis externa, swimming or participating in any aquatic activity, using earplugs, hot and humid weather, use of hearing aid, allergic diseases, and any illness in relationship with a decrease in the immune system. All except for the risk factor in association with the immune system will predispose to resurrect external otitis. On the other hand, the diseases with weak immune system predispose for both recurrent infection and a more severe presentation.

Any disease that halts the immune system well-functioning such as diabetes, cancer, chronic infectious diseases, and malnutrition, is detrimental to the body response to contagious germs. For that, they could ground the base for malignant bacteria to cause swimmer’s ear, but also, the odds that it can turn to necrotizing otitis highly increase.

What is the classification of this ear infection?

The classification of otitis externa is in six primary categories depending on the length and the basis of the infection. Acute diffuse otitis externa is an infection that tends to affect people in close relationship with water settings for that the name of “swimmer’s ear.” Acute localized otitis externa is in association with hair infection; therefore, with different bacteria (Staphylococcus species.)

Chronic otitis externa is the term for the infection of the outer ear for more than six weeks. Eczematous otitis externa is the ear inflammation in association with skin conditions that have immune system impairments (mostly allergies); these conditions predispose to further infections. Necrotizing otitis externa is a profound infection that goes through deeper tissues, primarily affecting patients with risk factors as a weakened immune system. Otomycosis or fungal otitis externa is a particular entity due to the microorganisms causing the infection.

What causes this ear infection?

The ear infection results from an imbalance in the ear tube due to multiple factors such as allergy, scratching lesions, foreign body, and swimming. These triggers prompt external otitis in different frequency being the most and least common allergy, and swimming, correspondingly. The more prevalent cause by far is the bacteria infection, and many of them in different situations can be the basis. Approximately 9 of every ten patients with external otitis would have a bacterial infection. The remaining patients would have a fungal infection or allergies.

The most common bacteria are Pseudomonas species. However, a wide range of bacteria could be implicated in this infection, including a specific skin microbe such as Staphylococcus aureus. Regarding fungal external otitis, in nearly all the cases, Aspergillus is involved. This fungus arises due to the overuse of antibiotic eardrops that ultimately kills both the good and the harmful bacteria residing within the ear canal.

An example of a purely inflammatory cause of external otitis is the eczematoid external otitis. This external otitis has an association with allergic diseases. The conditions are eczema, contact dermatitis, and sensitivity to topical medications. Moreover, an acute otitis media with the secretion of pus could mimic this external otitis to some extent, but when a careful look is given, the ear canal is intact. In this condition, there isn’t any microorganism causing infection; instead, there is a constant inflammation in susceptible patients.

What are the symptoms?

An extensive list of symptoms exists for otitis externa; however, some of them are more common than others. Typically before the onset of the symptoms, the patients have a history of vigorous ear cleaning, use of ear swabs, or had any form of water in the ear. The symptoms are usually within one ear. The affection of both of them is possible but not that common, with a predominance of more than two-thirds of the cases in the right ear.

Eight of every ten patients have ear pain, which ranges from mild to moderate in severity. It arises from one to two days after exposure to the possible triggers. If the ear pain becomes unbearable, it must raise the alarms because it could be necrotizing otitis. This acute otitis requires immediate medical care, and it is a real emergency.

Other symptoms are way more challenging to observe in this infection, for example, ear discharge, and itching, which occurs in just 15% and 2% of the cases correspondingly. The ear discharge can begin as a clear and odorless secretion, but then it changes to a yellow appearance with an awful smell. Itching is mostly in association with a fungal infection and chronic conditions. The remaining possible symptoms are hearing loss, ringing in the ears, ear fullness, or fever.

It is possible to find swollen lymph nodes around the neck because of the ear infection. Those represent little battlefields where your immune system is in the process of elimination of the infectious disease. They produce a particular feel when touched. It is sort of a bump under the skin of less of a half-inch in the neck.

What are the possible complications of ear infections?

Even though it is infrequent that this disease progresses to the point of complications, it is not impossible. They are mostly reserved for a particular group of people with a lack of a healthy immune system, previously mentioned.

The necrotizing otitis externa is the worst-case scenario for the progressing of this infection. Its definition comprises an insufferable ear pain that could have a change of skin color towards black and require immediate assessment and treatment. This condition could exist from a previous otitis externa that didn’t receive treatment.

Many other complications are possible, although less common to come upon. The mastoid bone (see image 1) is nearby the ear, and there is a possibility that the infection spreads to it. Chrondritis of the auricle is the spread of the disease to the cartilage composing this structure. And, the infection of the base of the skull with the erosion of the bone is feasible.

The infection could reach the brain and the nervous structures within the skull. The significance of this is a sign of alarm for the doctor. The likeliness of having sequelae is high. On the other hand, one of the complications with the best handling is cellulitis, which is a profound skin infection in the surroundings of the ear tissue.

Who affects the most otitis externa?

Otitis externa can affect throughout the whole life and nationwide in the United States all year. Nevertheless, it would be interesting to highlight some particular features of this infection.

It affects approximately 0,5% of the whole population yearly. It is a presumption but, the higher incidence of cases among the hot and humid times of the year (mostly summer) is in association with a rise in aquatic activities.

The group of people with more cases of external otitis are children between seven and twelve years. Then, there is a tendency for the young adult population and the elderly over 65 years to experience it more often. This last finding of the elderly population is per their higher use of hearing aid, which is in association with more external otitis.

How your doctor can diagnose an external ear infection?

The doctor would perform a simple external examination of the ear, which includes visual inspection and physical maneuvers. And then, with an otoscope, which is an apparatus for seeing the ear canal, he can determine the inflammation of the ear canal, with or without the involvement of the outer tympanic membrane. It would depend on this assessment and the symptoms, the probability of requiring further exams.

(IMAGE 2) Author: Anatomist90 (

The physical maneuvers are core for achieving a diagnosis. These maneuvers consist of putting pressure on the tragus (see image 2), or just tractioning the helix upwards. For considering positive either of those maneuvers, when done, they would prompt pain in the patient.

Furthermore, the evaluation of the ear canal through the otoscope would find redness, bulging, and narrowing of the channel. In healthy circumstances, the ear canal would be seen as a clean, pink, and wide tube. It is possible to find some discharge when evaluating the patient or even mild inflammation in the tympanic membrane.

The infection itself, through its manifestations, gives some hints to the doctor for diagnosing. Fungal otitis externa causes more itch than pain in their symptoms. Also, the thick white or grey secretion is often present. These symptoms are characteristic of the ear infection by this microorganism. On the contrary, the infection by Pseudomonas aeruginosa, which is the bacteria that mostly causes bacterial outer ear infection. Typically causes a yellow or green secretion out of the ear.

Special situations in the diagnose of ear infection.

Despite the simple approach I just mentioned, in exceptional cases, it is not enough. If treatment fails, or in population susceptible to get complications by otitis externa, other exams are a formal recommendation.

Microbiological exams such as gram staining and cultures are an indication for identifying the specific microorganism in the infection. When complications are a highly probable diagnosis, then images exam is an indication. The best for this scenario is the high-resolution computed tomography (CT), while magnetic resonance imaging (MRI) plays a secondary role, which would suit great for other circumstances.

What is the treatment for external otitis?

First, there must be an identification of the cause. To define if it is an ear infection or an inflammatory disease because the treatment varies widely. Overall treatment would focus on mitigating pain, and through ear drops, decrease swelling and fight the infection. The identification of the trigger is a must for avoiding it in the short and long term, such as water activities or allergic reactions.

The majority of cases will not have complications and with easy-access medication from a pharmacy, focusing on topical treatment, such as ear drops and painkillers. The infection could cease. A careful assessment of the ear canal is mandatory before using eardrops. If the tympanic membrane has a rupture, in other words, the ear drum is performed, then the eardrops would pass through directly to the middle ear and prompt complications.

The bacterial external otitis responds great to topical antibiotics such as antibiotic eardrops. Similarly, the fungal external otitis responds to antifungal eardrop, and the inflammatory external otitis to steroid eardrop, the latter might recur despite successful treatment.

In severe cases, topical treatment would not be enough. For necrotizing external otitis, for example, receiving oral or intravenous antibiotics should take place. The exact drug depends on the specific microorganism which is seen in the microbiological exams. Nevertheless, it is possible to not find a specific microorganism and to receive a broad treatment that covers all the possible sources of infection.

It is critical to not confuse ear infection and inflammatory external otitis, given that steroids eardrop (a corticosteroid) suppress the immune system. Therefore, even if topical therapy is suitable to diminish the swelling, using only steroids without antibiotics would enhance the bacterial of fungal growth. Indeed, it could deteriorate the situation.

Could my ear receive surgery?

It is reserved for the most complicated cases. The procedure’s name is surgical debridement and drainage. The necrotizing otitis externa and other complications of otitis externa are relieved with this approach.

When significant quantities of cerumen (earwax) exist, an otorhinolaryngologist with special equipment and microscopes performs this tiny surgery. This surgery is practically a requirement for the patients with fungal infection in the outer ear because they tend to produce plenty of cerumen.

When should I see some betterment after treatment?

If your physician scores the right diagnosis, the vast majority of otitis externa infections should see amelioration after two to three days after initiating antibiotic therapy; however, if this target is not met by that time. Then, some reconsiderations of diagnosis and treatment should be in your doctor’s head.

To entirely eliminate the infection, it would only take seven to ten days. Even though, sometimes, in complicated cases, the necessity for surgical intervention for resolving the condition is necessary.

How can you prevent your child from getting an ear infection?

The avoidance of the risk factors aforementioned is an effortless task and contributes significantly to prevention. Keeping the ear of your child dry is mandatory. Sometimes if the child is experiencing repetitive external otitis, the utilization of acidifying drops would help to prevent the infection in such cases.

The restraint of using cotton-based ear swabs for removing cerumen and education regarding its fair use should be given. The constant trauma in the ear canal ultimately is what develops many ear infection cases.

If I have symptoms, what should I do?

A proper assessment by a general practitioner should be enough. However, I did an otitis externa symptoms checker that would help you to identify if it is likely that your symptoms are by external otitis.

What do you think?

Written by Dr. Esteban Kosak

Doctor of Medicine - MD Recently Graduated from Medical School and inspired to aid the global population during this situation. I think that we shall no longer be waiting to see a doctor when we feel sick. Several times we feel disease searches in Google drive us to a rabbit hole and come out thinking that we may die of cancer or something very serious, given that symptoms may seem to fit a wide variety of illnesses. Since I recently graduated from medical school. I have all the medical information fresh in my mind. My thorough experience as an expert researcher allows me to very-well known the different diseases and conditions that affect human bodies. Empowered by the United Nations 17 Sustainable Development Goals (SGDs). I think that we all can provide a grain of sand to help humanity. That's why we created Symptoms.Care a place where you can come and screen your symptoms and find what different illnesses can be related to them. Armed with the right information you can instantly, discretely, secure and from the comfort of your home talk with a Doctor that can Evaluate your Symptoms and help you seek the right treatment.


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