Otitis externa (ear canal infection)

Summary

• Otitis externa, or ‘swimmer's ear’, is an infection of the outer ear canal skin and can occur in acute and chronic forms.
• Excessive water exposure and insertion of certain objects such as ear buds too deeply or too often into the ear canal are important causes.

Description

Otitis externa is an inflammation or infection of the outer ear canal, the passage leading from the external ear to the eardrum. It may develop when water, dirt or other debris gets into the ear canal. Since it is often associated with excess water in the ear canal, and frequently occurs in children and young adults who swim a great deal, the common name for this inflammation is "swimmer's ear".

Cause

• Swimmer's ear is often caused by excessive water exposure in the ear from swimming or even routine showering. When water pools in the ear canal (it may be trapped there by wax in the ears), the skin lining in the ear canal becomes soft and soggy and serves as a culture medium for bacteria. This moisture can cause the skin inside the ear canal to flake and itch. Scratching of the itch inside the ear canal with an ear bud or other object may allow bacteria or fungi to invade the skin of the ear canal, causing an infection.
• Acute otitis externa is commonly a bacterial infection caused by Streptococcus, Staphylococcus, or Pseudomonas types of bacteria.
• Chronic otitis externa can be caused by a bacterial infection, but it is more likely to be caused by chronic dermatitis of the ear canal. People with chronic skin conditions such as eczema, psoriasis, or seborrheic dermatitis are more prone to outer ear infections.
• Swimming in polluted water is a common cause of swimmer's ear, especially if there is already inflammation or broken skin: the bacteria in the water find the moist, inflamed ear canal an ideal environment.
• Hot and humid weather conditions promote the development of outer ear infections.
• Excessive and harsh cleaning of wax from the ears can lead to infection. Wax protects the ear canal from excessive moisture and harbours beneficial bacteria. Removing this protective barrier - particularly with fingernails or other sharp objects that can scratch the skin - makes it easier for an infection to take hold.
• Use of products such as bubble baths, shampoos, hair spray and hair dyes can irritate the ear canal and lead to an outer ear infection.
• Foreign objects are often placed in the ear by young children or enter the ear accidentally when someone tries to clean or scratch the ear. Foreign objects such as hearing aids and ear buds can cause chronic irritation.
• Insects may become trapped in the ear.
• Chronic drainage from middle ear disease may also infect the outer ear.
• Diabetes is often associated with a particularly severe form of otitis externa.

Symptoms

The following are common symptoms of otitis externa:

• Itching, and a feeling of fullness inside the ear canal is usually the first sign of infection.
• Swelling of the ear canal
• Watery discharge from the ear
• Severe pain and tenderness in the ear - especially when moving the head and jaw, or gently pulling the earlobe. Unlike a middle ear infection (otitis media), the pain of an ear canal inflammation or infection is worse when chewing, when pressing on the "tag" in front of the ear, or when moving the earlobe.  The pain also often worsens when the ear starts discharging.
• A foul-smelling, yellowish discharge from the ear
• Temporarily muffled hearing (caused by blockage of the ear canal)
• The ear canal may swell to such an extent that it becomes completely closed.
• Enlarged neck glands which may make it difficult to open the jaw

When to see a doctor

Consult your doctor if:

• The pain worsens or does not improve within 24 hours. In rare cases, the infection can spread and damage underlying bones and cartilage.
• You are experiencing dizziness or ringing in the ears - such symptoms may indicate a more serious problem.
• You notice a rash on your scalp or near your ear, you may have seborrheic dermatitis, for which your doctor can provide treatment.

Treatment

Home

Otitis externa is usually not dangerous and often resolves by itself within a few days. With mild infections, therefore, you may want to try alternative home treatments first.

• Whatever the cause, moisture and irritation will prolong the course of the problem. Avoid getting any more water in your ear until the infection clears up. While showering or swimming, use an earplug or cotton wool with Vaseline on the outside. Do not use plastic earplugs.
• Make sure there are no foreign objects in the ear. Small insects trapped in the ear can often be washed out with warm water. Suffocate a larger insect by filling the ear with mineral oil or see your doctor to have it removed. Removal of an object from the ear can be difficult and should only be attempted by a doctor. Usually this can be done in the doctor’s room. The most common ear injury related to foreign objects is inadvertent damage during removal of an object.
• If you suspect the eardrum is ruptured, do not insert anything (except as prescribed by a health professional) into the ear.
• Gently rinse the ear using a bulb syringe and warm saline solution or a half-and-half solution of white vinegar and warm water. Make sure the flushing solution is at body temperature. Cool or hot fluids in the ear may cause dizziness.
• To ease ear pain, apply a warm washcloth or a heating pad. There may be some drainage when the heat melts earwax.  Do not leave a child alone with a heating pad.
• Take paracetamol or a non-steroidal anti-inflammatory medicine or aspirin to relieve pain. Do not give aspirin to children.
• Avoid scratching the inside of the ear or using ear buds, as this will aggravate the irritated skin, and will often make the condition worse.
• A hearing aid should be left out as much as possible until swelling and discharge stops.

Symptoms to watch for during home treatment:

• Ear pain and itching that persists or worsens after a few days of home treatment
• Any ear discomfort lasting longer than a few days
• Swelling, redness or extreme pain in the ear canal, the opening to the ear canal, the external ear, or the skin around the external ear
• Discharge from the ear that does not appear to be earwax
• Ear symptoms accompanied by a fever (38 degrees C or higher)
• Dizziness or unsteadiness
• Increased severity or frequency of symptoms

Medication

Your doctor will probably clean your ear with a cotton-tipped probe or suction device to relieve irritation and pain.

The most common treatment consists of antibiotic eardrops with or without an oral antibiotic. You may be given prescription eardrops containing a combination of hydrocortisone to relieve the itching, and an antibiotic to fight the infection. In some situations a "wick" will need to be placed in the ear canal. This is impregnated with a cream or ointment containing cortisone and an antibiotic, and is left in place for 48 hours. Periodic suctioning of the ear canal helps to keep it open, remove debris, and decrease bacterial counts.

If the pain is severe, your doctor may suggest aspirin, paracetamol or some other over-the-counter pain medication. If the infection does not improve within three or four days, your doctor may prescribe an oral antibiotic.

Seborrheic dermatitis and eczema that affect the ear canal can be made tolerable with the use of steroid drops and creams. Other allergy-type treatments may also help itchy ears.

To use eardrops:

• First warm the drops to body temperature by rolling the container in your hands for a few minutes. Inserting cold eardrops can cause pain and dizziness.
• Have the person lie down, ear facing up.
• Place drops on the wall of the ear canal in small quantities so air can escape and drops can get into the ear. Gently wiggle the outer ear.
• You may find it easier to insert eardrops in a small child's ear by holding the child on your lap with their head down on your knees.

Standard treatments and preventative measures are often all that is needed to treat most forms of otitis externa, even chronic otitis externa. However, in diabetics or immunocompromised individuals, chronic otitis externa can become a serious disease (malignant otitis externa). Malignant otitis externa is a misnomer because it is not a tumour or a cancer, but rather an aggressive bacterial (Pseudomonas) infection of the base of the skull

Prevention

Otitis externa is usually preventable with the following measures:

• Keep your ears dry. If you are prone to infections, use earplugs or a bathing cap when showering or swimming. Afterwards, tilt and shake your head to drain water from your ears. Gently dry your ears with the corner of a tissue or towel, or use a blow dryer on its lowest setting held several centimetres from the ear.
• Put a few drops of rubbing alcohol or alcohol mixed with an equal amount of white vinegar into the ear after swimming or showering. This solution will increase the rate of evaporation of water in the ear canal and has antibacterial properties. Tilt your head and wiggle the outside of the ear so the solution gets to the bottom of the ear canal, then let the liquid drain out. You can also use non-prescription drops to prevent swimmer's ear.
• To create a protective coating for your ear canal before going swimming insert  one or two drops of mineral oil or baby oil into your ear. This is a good method when a dry, crusty skin condition exists.
• Avoid swimming in dirty water.
• If you wear a hearing aid, take it out as often as possible to give your ear a chance to dry out; a hearing aid can trap moisture in the ear canal.
• Be careful when cleaning your ears. Wipe the outer ear with a clean washcloth. Do not dig into the ear canal, especially with a pointed object. Do not scratch in your ears, or insert foreign objects, even ear buds.
• Keep soap and shampoo out of the ear canal, as these products can cause irritation and itching. A gentle, warm shower is usually all that is needed to remove dirt from the ear canal. Direct the water into the ear and then tip your head to let the water and dirt drain out. If dirt remains in the ear after a shower, use a bulb syringe filled with warm water to gently irrigate the ear canal.
• Try to keep the ear free of excess wax. This may require maintenance visits to the doctor to have your ears cleaned, or, if your ear will tolerate it, the use of an over-the-counter wax remover.
• If you already have an ear infection, if you have a hole in your eardrum, or if you have ever had ear surgery or ear tubes inserted, first consult your doctor before swimming or using any type of eardrop.
• In most cases, it is best to leave your ears alone and let them maintain their own healthy, natural balance.
• Do not put cotton swabs in the ear canal. Avoid prolonged use of earplugs. Both cotton swabs and earplugs can cause irritation and itching, and can plug the ear with wax.
• Follow instructions your doctor has given you to treat skin problems (eczema, psoriasis and seborrhea) that may cause ear canal irritation.

Previously reviewed by Dr D. Wagenfeld, M.B.Ch.B, M.Med, F.C.S.

Reviewed by Prof Eugene Weinberg, March 2011