Otitis externa ("swimmer's ear") is an
inflammationInflammation is the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli as well as initiate the healing process for the tissue. Inflammation is not a...
of the outer
earThe ear is the organ that detects sound. The vertebrate ear shows a common biology from fish to humans, with variations in structure according to order and species. It not only acts as a receiver for sound, but plays a major role in the sense of balance and body position...
and ear canal. Along with
otitis mediaOtitis media is inflammation of the middle ear, or middle ear infection.Otitis media occurs in the area between the ear drum and the inner ear, including a duct known as the eustachian tube. It is one of the two categories of ear inflammation that can underlie what is commonly called an earache,...
, external otitis is one of the two human conditions commonly called "earache". It also occurs in many other species. Inflammation of the
skinThe skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system made up of multiple layers of mesodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs. Skin of a different nature exists in amphibians, reptiles, birds...
of the ear canal is the essence of this disorder. The inflammation can be secondary to dermatitis (eczema) only, with no microbial infection, or it can be caused by active bacterial or fungal infection. In either case, but more often with infection, the ear canal skin swells and may become painful and/or tender to touch.
Acute
In contrast to the chronic otitis externa, acute otitis externa is predominantly a microbial infection, occurs rather suddenly, rapidly worsens, and becomes very painful and alarming. The ear canal has an abundant nerve supply, so the pain is often severe enough to interfere with sleep. Wax in the ear can combine with the swelling of the canal skin and any associated pus to block the canal and dampen hearing to varying degrees, creating a temporary conductive hearing loss. In more severe or untreated cases, the infection can spread to the soft tissues of the face that surround the adjacent
parotid glandThe parotid gland is the largest of the salivary glands. It is found wrapped around the mandibular ramus, and it secretes saliva through Stensen's duct into the oral cavity, to facilitate mastication and swallowing.-Location:...
and the jaw joint, making chewing painful. In its mildest forms, external otitis is so common that some ear nose and throat physicians have suggested that most people will have at least a brief episode at some point in life. While a small percentage of people seem to have an innate tendency toward chronic external otitis, most people can avoid external otitis altogether once they understand the
mechanisms of the disease.
The skin of the bony ear canal is unique, in that it is not movable but is closely attached to the bone, and it is almost paper thin. For these reasons it is easily abraded or torn by even minimal physical force. Inflammation of the ear canal skin typically begins with a physical insult, most often from injury caused by attempts at self-cleaning or scratching with cotton swabs, pen caps, finger nails, hair pins, keys, or other small implements. Another causative factor for acute infection is prolonged water exposure in the forms of swimming or exposure to extreme humidity, which can compromise the protective barrier function of the canal skin, allowing bacteria to flourish; hence the name, "swimmer's ear". Densely impacted wax, usually caused by enthusiastic use of cotton swabs, can put enough pressure on the ear canal skin to injure it and initiate infection. A sensation of blockage or itching can prompt attempts to clean, scratch, or open the ear canal, which potentially worsens and perpetuates the condition. The cotton fibers of a swab are abrasive to the thin, fixed canal skin. Self-manipulative measures to improve the condition often make it worse and are to be discouraged, since it is a blind exercise that can result in significant injury to the ear. Production of wax by glands in the canal may be hindered by external otitis. The exact function(s) of cerumen (earwax) is a subject that is open to speculation, since there is very little research regarding its function. Some caretakers feel strongly that earwax has a protective function with respect to infection and that a little earwax in the ear canal is a good thing. A natural question is, "How can I clean my ears, then?" It is well established that in most people the top layer of the ear canal skin normally migrates toward the ear opening, essentially sweeping the canal on a continuing basis. In other words, a normal ear canal is self-cleaning. This self-cleaning physiologic feature fails in some patients, especially in late life, and
periodic cleaning by a physician can be necessary. The most controlled and least painful means of cleaning impacted wax or dead skin from the ear canal is by using a binocular surgical microscope, which frees the examiner's hands to instrument the ear and provides the magnification and depth perception needed to avoid traumatizing the delicate canal skin and eardrum.
Symptoms
PainPhysical Pain is the unpleasant feeling common to a headache and a stubbed toe. It typically consists of negative affect and aversion, and has location, duration, intensity and a distinctive quality...
is the predominant complaint and the only symptom directly related to the severity of acute external otitis. Unlike other forms of ear infections,
the pain of acute external otitis is worsened when the outer ear is touched or pulled gently. Pushing the tragus, the tablike portion of the auricle that projects out just in front of the ear canal opening, so typically causes pain in this condition as to be diagnostic of external otitis on physical examination. Patients may also experience ear discharge and itchiness. When enough swelling and discharge in the ear canal is present to block the opening, external otitis may cause temporary conductive hearing loss.
Due to the fact that the ear and throat are often interconnected, irritation (whether it be in inflammation or a scratching sensation) is normal. However, excessive throat symptoms may likely point to the throat as the cause of the pain in the ear rather than the other way around.
Because the symptoms of external otitis promote many people to attempt to clean out the ear canal (or scratch it) with slim implements, and self-cleaning attempts generally lead to additional trauma of the injured skin, rapid worsening of the condition often occurs.
Causes, incidence, and risk factors
Swimming in polluted water is a common way to contract swimmer's ear, but it is also possible to contract swimmer's ear from water trapped in the ear canal after a shower, especially in a humid climate. Constriction of the ear canal from bone growth (
Surfer's earSurfer's Ear is the common name for an exostosis or abnormal bone growth within the ear canal. Surfer's ear is not the same as swimmer's ear, although infection can result as a side-effect....
) can trap debris leading to infection.
Saturation diversSaturation diving is a diving technique that allows divers to remain at great depth for long periods of time."Saturation" refers to the fact that the diver's tissues have absorbed the maximum partial pressure of gas possible for that depth due to the diver being exposed to breathing gas at that...
have reported Otitis externa during occupational exposure. Even without exposure to water, the use of objects such as
cotton swabCotton swabs consist of a small wad of cotton wrapped around either one or both ends of a small rod, usually made of either wood, rolled paper, or plastic...
s or other small objects to clear the ear canal is enough to cause breaks in the skin, and allow the condition to develop. Once the skin of the
ear canal is inflamed, external otitis can be drastically enhanced by either scratching the ear canal with an object, or by allowing water to remain in the ear canal for any prolonged length of time.
The two factors that are required for external otitis to develop are (1) the presence of
germsA pathogen , infectious agent, or germ, is a biological agent that causes disease or illness to its host....
that can infect the skin and (2) impairments in the integrity of the skin of the ear canal that allow infection to occur. If the skin is healthy and uninjured, only exposure to a high concentration of pathogens, such as submersion in a pond contaminated by
sewageSewage is water-carried wastes, in either solution or suspension, that flow away from a community. Also known as wastewater flows, sewage is the used water supply of the community. It is more than 99.9% pure water and is characterized by its volume or rate of flow, its physical condition, its...
, is likely to set off an episode. However, if there are chronic skin conditions that affect the ear canal skin, such as
atopic dermatitisAtopic dermatitis is an inflammatory, chronically relapsing, non-contagious and pruritic skin disease. It has been given names like "prurigo Besnier," "neurodermitis," "endogenous eczema," "flexural eczema," "infantile eczema," and "prurigo diathsique".-Presentation:The skin of a patient with...
, seborrheic dermatitis,
psoriasisPsoriasis is a chronic, non-contagious autoimmune disease that affects the skin and joints. It commonly causes red, scaly patches to appear on the skin. The scaly patches caused by psoriasis, called psoriatic plaques, are areas of inflammation and excessive skin production. Skin rapidly...
or abnormalities of
keratinKeratins are a family of fibrous structural proteins; tough and insoluble, they form the hard but un-mineralized structures found in reptiles, birds, amphibians, and mammals...
production, or if there has been a break in the skin from trauma, even the normal bacteria found in the ear canal may cause infection and full-blown symptoms of external otitis.
Fungal ear canal infections, also known as
otomycosisOtomycosis is a fungal ear infection, a superficial mycotic infection of the outer ear canal. It is more common in the tropical countries. The infection may be either subacute or acute and is characterized by inflammation, pruritus, scaling, and severe discomfort...
, range from inconsequential to very severe. Fungus can be saprophytic, in which there are no symptoms and the fungus simply co-exists in the ear canal in a harmless parasitic relationship with the host, in which case the only physical finding is presence of the fungus. If for any reason the fungus begins active reproduction, the ear canal can fill with dense fungal debris, causing pressure and ever-increasing pain that is unrelenting until the fungus is removed from the canal and anti-fungal medication is used. Most antibacterial ear drops also contain a steroid to hasten resolution of canal edema and pain. Unfortunately such drops make fungal infection worse. Prolonged use of them promotes growth of fungus in the ear canal. Antibacterial ear drops should be used a maximum of one week, but 5 days is usually enough. Otomycosis responds more than 95% of the time to a three day course of the same over-the-counter anti-fungal solutions used
for athlete's foot.
The incidence of otitis externa is high. In the Netherlands, it has been estimated at 12-14 per 1000 population per year, and has been shown to affect more than 1% of a sample of the population in the United Kingdom over a 12 month period.
Pathogens
The bacterial pathogens at the top of the list are
Pseudomonas aeruginosaPseudomonas aeruginosa is a common bacterium which can cause disease in animals and humans. It is found in soil, water, skin flora and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also with little oxygen, and has thus colonised many natural and...
and
Staphylococcus aureusStaphylococcus aureus is the most common cause of staph infections. It is a spherical bacterium, frequently part of the skin flora found in the nose and on skin. About 20% of the population are long-term carriers of S. aureus. S...
, followed by a great number of other gram-positive and gram-negative species.
Candida albicansCandida albicans is a diploid fungus and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections have emerged as important causes of morbidity and mortality in immunocompromised patients...
and
AspergillusAspergillus is a genus of a few hundred molds found throughout much of nature worldwide. Aspergillus was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Micheli was reminded of the shape of an aspergillum , and named the genus...
species are the most common fungal pathogens responsible for the condition.
Diagnosis
When the physician looks in the ear, the canal appears red and swollen in well-developed cases of acute external otitis. The ear canal may also appear
eczemaEczema is a disease in a form of dermatitis, or inflammation of the epidermis. The term eczema is broadly applied to a range of persistent skin conditions. These include dryness and recurring skin rashes that are characterized by one or more of these symptoms: redness, skin edema , itching and...
-like, with scaly shedding of skin. Touching or moving the outer ear increases the pain, and this maneuvre on physical exam is very important in establishing the clinical diagnosis. It may be difficult for the physician to see the
eardrumThe tympanic membrane , is a thin membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air to the ossicles inside the middle ear. The malleus bone bridges the gap between the eardrum and the other ossicles...
with an
otoscopethumb|right|200px|Otoscope - Image of an otoscope thumb|200px|Anatomy of the human ear.thumb|200px|Right tympanic membrane as seen through a speculum.An Otoscope or auriscope is a medical device which is used to look into the ears...
at the initial examination because of narrowing of the ear canal from inflammation and the presence of drainage and debris. Sometimes the diagnosis of external otitis is presumptive and return visits are required to fully examine the ear. Culture of the drainage may identify the bacteria or fungus causing infection, but is not part of the routine diagnostic evaluation. In severe cases of external otitis, there may be swelling of the
lymph nodeA lymph node is an organ consisting of many types of cells, and is a part of the lymphatic system. Lymph nodes are found all through the body, and act as filters or traps for foreign particles. They contain white blood cells that use oxygen to process. Thus they are important in the proper...
(s) directly beneath the ear.
The diagnosis may be missed in early cases because the examination of the ear, with the exception of pain with manipulation, is normal or nearly normal. In some cases of early external otitis, the most striking visual finding in the ear canal is the lack of cerumen. As a moderate or severe case of external otitis resolves, weeks may be required before the ear canal again shows a normal amount of cerumen.
Treatment
The goal of treatment is to cure the infection and to return the ear canal skin to a healthy condition. When external otitis is very mild, in its initial stages, simply refraining from swimming or washing hair for a few days, and keeping all implements out of the ear, usually results in a cure. For this reason, external otitis is called a self-limiting condition. However, if the infection is moderate to severe, or if the climate is humid enough that the skin of the ear remains moist, spontaneous improvement may not occur.
Topical solutions or suspensions in the form of ear drops are the mainstays of treatment for external otitis. Some contain antibiotics, either antibacterial or antifungal, and others are simply designed to mildly acidify the ear canal environment to discourage bacterial growth. Some prescription drops also contain anti-inflammatory steroids, which help to resolve swelling and itching. Although there is evidence that steroids are effective at reducing the length of treatment time required, fungal otitis externa (also called otomycosis) may be caused or aggravated by overly prolonged use of steroid-containing drops. In addition to topical antibiotics, oral anti-pseudomonal antibiotics can be used in case of severe soft tissue swelling extending into the face and neck and may hasten recovery.
Removal of debris (wax, shed skin, and pus) from the ear canal promotes direct contact of the prescribed medication with the infected skin and shortens recovery time. This is best accomplished using a binocular microscope. When canal swelling has progressed to the point where the ear canal is blocked, topical drops may not penetrate far enough into the ear canal to be effective. The physician may need to carefully insert a wick of cotton or other commercially available, pre-fashioned, absorbent material called an ear wick and then saturate that with the medication. The wick is kept saturated with medication until the canal opens enough that the drops will penetrate the canal without it. Removal of the wick does not require a health professional. Antibiotic ear drops should be dosed in a quantity that allows coating of most of the ear canal and used for no more than 4 to 7 days. The ear should be left open. Do note that it is imperative that there is visualization of an intact tympanic membrane (eardrum).
Use of certain medications with a ruptured tympanic membrane can cause tinnitus, vertigo, dizziness and hearing loss in some cases.
Although the acute external otitis generally resolves in a few days with topical washes and antibiotics, complete return of hearing and cerumen gland function may take a few more days. Once healed completely, the ear canal is again self-cleaning. Until it recovers fully, it may be more prone to repeat infection from further physical or chemical insult.
Effective medications include
ear dropEar drops are a form of medicine used to treat or prevent ear infections, especially infections of the outer ear and ear canal .Bacterial infections are sometimes treated with antibiotics...
s containing
antibioticIn common usage, an antibiotic is a substance or compound that kills or inhibits the growth of bacteria...
s to fight infection, and
corticosteroidCorticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
s to reduce itching and inflammation. In painful cases a topical solution of antibiotics such as aminoglycoside, polymyxin or fluoroquinolone is usually prescribed. Antifungal solutions are used in the case of fungal infections. External otitis is almost always predominantly bacterial or predominantly fungal, so that only one type of medication is necessary and indicated.
The pain of acute otitis externa is often severe enough to interfere with sleep. Topical analgesic drops often prescribed by primary care providers for pain relief are almost never adequate and should not be relied upon. A brief course of oral narcotic pain medication is often necessary to maintain comfort while the antibiotic drops are working. Improvement with appropriate initial treatment (cleaning of the canal, wick insertion if necessary, and antibiotic drops in adequate amount) is fairly rapid, with pain improvement occurring within one day and resolution within 2-4 days. Heat application using a heating pad, can also aid in pain relief, although it may increase the bacteria growth.
Non-prescription remedies
Provided it is not too severe, recurrent otitis externa can often be successfully treated by non-prescription means, at low cost.
When symptoms recur in an individual who has had a previous diagnosis made, the use of non-prescription drops along with precautions to keep water out of the ear is generally effective. Self-treatment with non-prescription remedies is dangerous in individuals who have not been previously evaluated for the condition, because the tympanic membrane may not be intact, and because the true condition may be otitis media with drainage. Drops and water precautions may actually resolve otitis media with drainage for a period of time, while allowing an undiagnosed
cholesteatomaCholesteatoma is a destructive and expanding keratinizing squamous epithelium in the middle ear and/or mastoid process.-Causes:There are two types: congenital and acquired. Acquired cholesteatomas can be caused by a tear or retraction of the ear drum....
to progress, or complications of otitis media to develop.
Effective solutions for the ear canal include acidifying and drying agents, used either singly or in combination. When the ear canal skin is inflamed from the acute otitis externa, the use of dilute
acetic acidAcetic acid, CH
3COOH, also known as ethanoic acid, is an organic acid which gives vinegar its sour taste and pungent smell. It is a weak acid, in that it is only partially dissociated acid in aqueous solution...
may be painful.
Burow's solutionBurow's solution is a pharmacological preparation made of aluminium acetate dissolved in water. It was invented in the mid-1800s by Karl August Burow, an ophthalmologist....
is an effective remedy against both bacterial and fungal external otitis. This is a buffered mixture of
aluminium sulfateAluminium sulfate or Aluminium Sulphate, written as Al23 or Al2O12S3 Aluminium sulfate is an industrial chemical used as a flocculating agent in the purification of drinking water and waste water treatment plants, and also in paper...
and
acetic acidAcetic acid, CH
3COOH, also known as ethanoic acid, is an organic acid which gives vinegar its sour taste and pungent smell. It is a weak acid, in that it is only partially dissociated acid in aqueous solution...
, and is available without prescription in the United States.
Prevention
The strategies for preventing acute external otitis are similar to those for treatment.
- Avoid inserting anything into the ear canal; use of cotton buds or swabs is the most common event leading to acute otitis externa.
- Most normal ear canals have a self-cleaning and self-drying mechanism, the latter by simple evaporation.
- After prolonged swimming, a person prone to external otitis can dry the ears using a small battery-powered ear dryer, available at many retailers, especially shops catering to watersports enthusiasts. Alternatively, drops containing dilute acetic acid (vinegar diluted 3:1) or Burow's solution may be used. It is especially important NOT to instrument ears when the skin is saturated with water, as it is very susceptible to injury, which can lead to external otitis.
- Avoid swimming in polluted water.
- Avoid washing hair or swimming if very mild symptoms of acute external otitis begin
- Although the use of earplugs when swimming and shampooing hair may help prevent external otitis, there are important details in the use of plugs. Hard and poorly fitting ear plugs can scratch the ear canal skin and set off an episode. When earplugs are used during an acute episode, either disposable plugs are recommended, or used plugs must be cleaned and dried properly to avoid contaminating the healing ear canal with infected discharge. One simple method of fabricating soft waterproof disposable ear plugs is with cotton balls and petroleum jelly
Petroleum jelly, petrolatum or soft paraffin, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons , originally promoted as a topical ointment for its healing properties...
. These jelly coated cotton balls are NOT inserted into the ear canal, but pressed into the auricle to cover the opening of the canal. Poorly fitted head sets can also bring on an episode caused by friction between the ear and phone muffs. It is important to wear small head phones that do not cover the whole ear.
Prognosis
Otitis externa responds well to treatment, but complications may occur if it is not treated. Individuals with underlying diabetes or disorders of the immune system are more likely to get complications, including malignant otitis externa. In these individuals, rapid examination by an otolaryngologist (ear, nose, and throat physician) is very important.
Complications
- Chronic otitis externa
- Spread of infection to other areas of the body
- Necrotizing External Otitis
Necrotizing External Otitis (Malignant otitis externa)
This uncommon form of external otitis occurs mainly in elderly diabetics, being somewhat more likely and more severe when the diabetes is poorly controlled. Even less commonly, it can develop due to a severely compromised immune system. Beginning as infection of the external ear canal, there is extension of infection into the bony ear canal and the soft tissues deep to the bony canal. The hallmark of malignant otitis externa (MOE) is unrelenting pain that interferes with sleep and persists even after swelling of the external ear canal may have resolved with topical antibiotic treatment.
Natural History
MOE follows a more chronic course than ordinary acute otitis externa. There may be granulation involving the floor of the external ear canal, most often at the bony-cartilaginous junction. Paradoxically, the physical findings of MOE, at least in its early stages, are often much less dramatic than those of ordinary acute otitis externa. In later stages there can be soft tissue swelling around the ear, even in the
absence of significant canal swelling. Also it can hurt the tip of your throat, causing pain when touched.
Treatment
Unlike ordinary otitis externa, MOE requires oral or intravenous antibiotics for cure. Diabetes control is also an essential part of treatment. When MOE goes unrecognized and untreated, the infection continues to smolder and over weeks or months can spread deeper into the head and involve the bones of the skull base, constituting skull base osteomyelitis
(SBO). The infecting organism is almost always pseudomonas aeruginosa, but it can instead be fungal (aspergillus or mucor). MOE and SBO are not amenable to surgery, but exploratory surgery may facilitate culture of unusual organism(s) that are not responding to empirically used anti-pseudomonal antibiotics. The usual surgical finding is diffuse cellulitis without localized abscess formation. SBO can extend into the petrous apex of the temporal bone or more inferiorly into the opposite side of the skull base.
Complications
As the skull base is progressively involved, the adjacent exiting cranial nerves and
their branches, especially the facial nerve and the vagus nerve, may be affected, resulting in facial paralysis and hoarseness, respectively. If both of the recurrent laryngeal nerves are paralyzed, shortness of breath may develop and necessitate tracheotomy. Profound deafness can occur, usually later in the disease course due to relative resistance of the inner ear structures. Gallium scans are sometimes used to document the extent of the infection but are not essential to disease management. Skull base osteomyelitis is a chronic disease that can require months of IV antibiotic treatment, tends to recur, and has a significant mortality rate.
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