We could finally afford a swimming pool in the backyard. All summer the family was together, and we had barbecues and invited the neighbors over. But now every time the kids get in the water, their ears start to itch. When they begin to hurt and drain green goop, it means another trip to the family doctor, more ear drops, and no swimming for a week.
Swimmer’s ear is the usual term for acute otitis externa, an infection of the outer ear canal. External otitis affects approximately four people in every thousand each year. Not surprisingly, 80 percent of these infections occur in the summer. Factors that play a role in external otitis besides swimming include living in a humid environment, frequent use of a hot tub, narrowing of the ear canal by wax impaction or bony growth, and use of cotton swabs.
After showering or swimming it is common to experience itching in the ears. Unfortunately, the skin of the ear canal is easily injured by using a cotton swab or fingernail to scratch the itch. By removing the protective layer of wax and by damaging the delicate layer of skin lining the ear canal cotton swabs may lead to external otitis.
Anatomy of an Infection
The ear canal is an opening in the skull that allows sound to reach the eardrum. The outer third of the canal is lined with cartilage and covered by skin. The inner two-thirds of the canal is lined with skin growing directly on bone. The skin of the outer third has wax glands that produce the protective coating of the skin called cerumen (see chapter 1).
Figure 12.1
Clinical appearance of swimmer’s ear. Note that the skin is infected and swollen resulting in narrowing of the ear canal. The narrowing can progress to complete obstruction in some cases. Infected material is draining out of the ear canal and can cause a red bumpy rash on the outer skin.
Swimmer’s ear can be caused by bacteria or fungi. Bacteria are normally present on the canal skin, as they are on all skin. In most cases, wax protects the skin from microbes. But when wax has been wiped away by cotton swabs, prolonged water contact with skin of the canal (such as swimming) reduces resistance to bacteria or fungi. The same process occurs when the skin is broken by scratching it.
Bacterial Infection
Bacterial infections make up about 95 percent of acute external otitis in temperate climates. The most common bacteria to cause external otitis are Pseudomonas (40 percent) and Staphylococcus (25 percent), both of which tend to be resistant to commonly used oral antibiotics such as amoxicillin but sensitive to antibiotic ear drops. The most prominent symptom is ear pain and tenderness. The doctor will look into the ear with an otoscope slowly and carefully, since the infection may cause tenderness. The doctor may need to remove infected debris to see the canal properly.
Fungal Infection
Fungal infections account for less than 5 percent of acute external otitis and are even less common in dry climates. Candida albicans is a white yeast that can cause a mild infection, especially in people who wear hearing aids. This is the result of the buildup of moisture under the hearing aid, irritation of the skin of the ear canal, and rubbing away of the wax layer.
Another fungi, Aspergillus, causes more serious infections that may be more difficult to eradicate. Aspergillus fungus produces creamy, thick, and sticky discharge. Fungal infections can often be identified by the presence of tiny bristles (the fungus itself) that are often black. When the organism causing swimmer’s ear is easily identified, a culture may not be necessary if treated early. In cases of resistance to treatment or in advanced cases, a culture is indicated.
Prevention of Acute Otitis Externa
Some children and adults have recurring episodes of otitis externa. The first step in management is to be certain that infections are completely cleared and the ear canal skin and cerumen are back to normal before allowing water to enter the ears. This may require two to six weeks of dry ear precautions. The authors recommend placing a compact cotton ball in the ear canal opening, then covering the outside of the cotton with petroleum jelly to prevent water penetration. This method has the advantage of using disposable and non-damaging cotton. Reusing plastic ear plugs may prolong infections by re-contaminating the ear as well as by damaging fragile skin.
Cotton swabs, fingernails, and all other objects must be kept out of the ears. The smallest bruise or scratch may lead you right back to the doctor’s office and the more times infection occurs, the more vulnerable the ear is to re-infection.
Staying out of the pool or the lake may not be practical during a vacation or hot summer weather, but it is the most effective prevention for many people. Keeping most water out of the ears is possible for surface swimmers by using ear plugs.
When using ear plugs, ear drops with acetic acid (white vinegar), alcohol, or a 50/50 combination of acetic acid and rubbing alcohol can be helpful after swimming. These preventative drops help evaporate moisture that got past the plugs while reducing bacterial growth by being slightly acidic. Ear dryers, available in pharmacies and online, are also useful to remove moisture from the ears (see below).
Ear Plugs
Many different types and styles of ear plugs are available. Your doctor will recommend a type that has worked well for his or her patients and your local pharmacy will have a number of brands you can try. The variety is even larger online.
Be sure to get the plugs designed for swimming rather than noise protection. One effective type is a moldable silicone plug that is custom fit at home. One drawback of using ear plugs is that they tend to leak a bit. Try to find a brand that makes a secure seal in your ear. For the most part, over-the-counter ear plugs work as well as the $100 custom plugs at the audiology office. Headbands are also available to keep the plugs from falling out. Be sure to wash the plugs carefully and allow them to dry before re-use.
Drying the Ear Canal after Swimming
If water enters the ear canal it can be partially removed. Place a piece of tissue into the ear opening. It does not need to go in more than 1/10 inch; just breaking the surface tension will cause the water to wick out.
Hair dryers can also be used for this purpose, although they are not especially effective since circulation of air cannot be established in the ear canal. Pull the ear back gently to open the canal, place the dryer on low heat at least 6 inches away for about two minutes.
Specialized ear dryers are also available. Rather than blowing from the outside, these have a safety tip that extends a short distance into the canal. Some blowers have an electrical fan and others use a squeeze bulb to get the air flowing. They are available online as well as in many pharmacies.
An alternate method of drying the ear canal is to use over-the-counter drops that contain a rapidly evaporating liquid like alcohol after swimming. Of course these products cannot be used if there is a hole in the eardrum and are usually not adequate to treat an existing infection. A variety of liquid drying agents can also be found online and in pharmacies. Beware of hydrogen peroxide containing drops that are designed for wax removal. These can damage and further reduce the skin’s resistance to infection.
Table 12.1
Preventing Swimmer’s Ear
|
Method |
Description |
Timing |
|
Ear plugs |
moldable silicone |
Before swim |
|
Acidifying drops |
2% acetic acid |
Before/after swim |
|
Drying drops |
vinegar/alcohol |
After swim |
|
Air dryers |
electric fan or bulb |
After swim |
Two percent acetic acid (Domboro Otic, Vosol) is used to prevent infections by slightly acidifying the ear canal. The acid environment can keep both bacteria and fungi from getting a foothold. At times, acetic acid drops are also used to treat an established infection. Acetic acid ear drops are available by prescription or over the counter at most pharmacies or online.
A solution of half alcohol and half vinegar is very effective in preventing swimmer’s ear and can be mixed at home. Again, be sure to check with your doctor for directions before starting any treatment. In resistant cases, a combination approach may be called for. Place drops in the ear canal, then slowly insert ear plugs before swimming. After swimming, remove plugs, dry the ear with a blower then add more drops.
Table 12.1 summarizes prevention of swimmer’s ear.
Treatment of Acute Otitis Externa
Dry Ear Precautions
By keeping the ear totally dry and using prescribed antibiotic ear drops you can usually clear up an infection in the early stages within a few days. Amoxicillin is not indicated for external otitis. Dry ear precautions are critical to getting better—no cheating. If the ear is draining, it is fine to catch the drainage with a loose piece of cotton, but do not block the opening, trapping pus inside. The cotton should be changed when moist.
Absolutely no swimming or water in the ear should be permitted until your doctor clears you. This may be two to six weeks after the infection is eliminated. When showering, protect the ear canal by placing a cotton ball firmly in the opening. The outside (only) of the cotton ball should be coated with petroleum jelly in order to keep moisture out. Petroleum jelly–coated cotton balls are better for this purpose than store-bought ear plugs because they are less traumatic to insert and can be thrown away afterwards, rather than re-used—minimizing the risk of re-infection. When bathing, rather than showering, do not submerge your head in the bath water.
Antibiotic Ear Drops
Antibiotic ear drops are preferred over oral antibiotics. Some antibiotics cannot be taken by mouth or injection, and the concentration of antibiotics in ear drops is much higher than can be achieved by oral antibiotics. However, for advanced bacterial infections that invade the deeper tissues, or for people whose immune systems are weakened, oral or injectable antibiotics may also be necessary.
Some common antibiotic drops include neomycin and polymyxin B (beware, 10 percent of the population may become allergic to neomycin), ciprofloxacin (Cetraxal), ofloxacin (Floxin Otic), and gentamicin. Ear drops that contain antibiotics usually require a prescription. Antibiotic ear drops are often combined with steroid solutions in order to reduce swelling, inflammation, and pain.
When swimmer’s ear is caused by a fungus, it is also treated by meticulous cleaning and drops containing acetic acid. Antifungal drops, such as nystatin and clotrimazole, can be effective in treating the fungus Candida but are less effective in treating the common Aspergillus fungi. Your ear specialist may apply antifungal liquids to the ear canal, such as gentian violet or Cresylate, after cleaning. If topical methods are not effective, oral itraconizole may be prescribed but has a small risk of complications that involve the heart and liver.
Referral to an Ear Specialist
If simple treatment methods are not effective, you will be referred to an ear specialist. External otitis creates infectious debris that can block drops from reaching the bacteria or fungi. Your ear specialist’s first step is to culture and remove the pus or debris using an ear microscope. Careful cleaning reduces the number of bacteria or fungi and allows the drops to reach the infected skin surface. Repeat cleaning may be necessary every few days.
In more advanced cases of otitis externa, the skin swells and may even close off the ear canal. This usually occurs when the infection has invaded the tissues under the skin lining and is called cellulitis. Cellulitis is a very painful situation and the swelling will prevent the drops from reaching infected tissue. When the ear canal is swollen shut, your ear specialist may need to insert an expanding wick. The wick will gradually open the canal and bring antibiotic drops to the infected area. Insertion can be momentarily painful but will usually result in quick relief of discomfort. Cellulitis generally requires oral antibiotics as well as antibiotic drops.
Complications
Chronic Dermatitis and Otitis Externa
Outer ear infections may come and go frequently over many years. This is generally caused by an underlying condition of the skin. Seborrheic dermatitis is similar to dandruff and often occurs in the scalp, eyebrows, and ear canal. It reduces the ear canal skin’s ability to fight infection.
In cases of recurrent otitis externa, the present episode is treated in the usual way (dry ear precautions, antibiotic ear drops, etc.). Once the acute infection is controlled, it is time to treat the underlying skin condition that would otherwise lead to further infections. Seborrheic dermatitis can be treated with oil-based steroid drops.
Psoriatic dermatitis also affects the ear canal and is a more severe but less common disorder than seborrhea. Psoriasis causes a red, flaking rash but with thick silvery scales and plaques that can bleed when removed. It is also common on the elbows and knees. In some cases, psoriasis and otitis externa should be jointly managed by ear and skin specialists.
Chronic itchy ear may also result from the skin condition called eczema, which is a red, itchy rash, usually of unknown cause. Dermotic is an oil-based steroid ear drop that may be used in such cases. Sometimes it is necessary to stop all medications to allow the skin time to recover.
Contact dermatitis of the ear canal can also result from the use of hearing aids, hairsprays, and ear drops that contain neomycin. The allergic rash is red and bumpy and appears at the opening of the canal or where the drops overflow onto the pinna. Once recognized, it is usually treated with topical steroids and withdrawal of the offending substance. Hearing aids that irritate the skin can also be replaced by a type made with non-allergenic plastics.
Spread of Infection
Infection of the outer layers of skin can spread to involve the deep layers (cellulitis), the cartilage lining (perichondritis), the cartilage itself (chondritis), or bone (osteitis). Culture of the infection is necessary along with prescription use of oral or injectable antibiotics. Quinolone antibiotics are the drugs of choice (for example, ciprofloxacin), having been shown to be safe and effective in children and adults.
When the cartilage lining is infected (perichondritis), the outer ear swells and turns red. The skin becomes very firm. As with cellulitis, the common bacteria found are pseudomonas and staphylococcusspecies and the drug of choice is a quinolone antibiotic. If a mushy soft area is present, it may represent an abscess (accumulation of pus) and must be drained. This fluid under the skin can also indicate that the cartilage itself is infected (chondritis). Infected cartilage often must be cut away because blood supply of cartilage is too meager for the antibiotics to be effective. Rarely, a non-infectious inflammatory condition involving cartilage in several areas of the body may mimic infectious chondritis of the outer ear. This may be caused by an autoimmune process and require steroid treatment.
Special Caution: Diabetes and Immune Suppression
Older people with diabetes, especially if it is poorly controlled, are at risk for a very aggressive form of external otitis. The same is true for people who have had organ transplants, HIV, are taking high doses of steroids, or undergoing cancer chemotherapy. All share a difficulty fighting infection because their immune systems are compromised by the underlying illness or treatment.
In people whose immune systems are suppressed (people who are said to be immunosuppressed), a simple bacterial or fungal infection may invade the underlying tissues and begin to spread through the bones of the skull. An earlier term for this condition was malignant otitis externa, but that term has largely been replaced by the terms necrotizing otitis externa or skull base osteomyelitis.
The diagnosis of skull base osteomyelitis is based on a high degree of suspicion when a patient with a weakened immune system gets an ear infection. Its hallmark symptoms are ear drainage and deep head pain.
Delay in diagnosis or appropriate treatment can lead to severe, chronic skull infection, and fatalities have been reported. The diagnosis requires microscopic cleaning of the ear canal and observation for granulation tissue, a reddish buildup of tiny blood vessels in response to bone infection of the ear canal. CT, MRI, and other imaging studies can be used to confirm the diagnosis and chart the progress of treatment. In many cases, the patient is hospitalized and placed on a combination of long-term intravenous antibiotics. Sometimes, healthy young patients who are identified early may be treated without hospitalization.