Ear canal infection is caused by bacteria or, less commonly, fungi.
Typical symptoms are pain and discharge.
A doctor looks in the ear with an otoscope for redness, swelling, and pus.
Debris removal, antibiotic ear drops, keeping water and cotton swabs out of the ear, and pain relievers are the most common forms of treatment.
Infection may involve the entire ear canal, as in generalized or acute external otitis, or just one small area, as when pus accumulates in a boil (furuncle) or pimple. Malignant external otitis is a rare, very severe external ear infection that has spread to the temporal bone of the skull, causing a bone infection (osteomyelitis).
A variety of bacteria, such as Pseudomonas aeruginosa or Staphylococcus aureus, can infect the ear canal. Fungal ear canal infection (otomycosis), typically caused by Aspergillus niger or Candida albicans, is less common. Boils are usually caused by Staphylococcus aureus.
Common risk factors for ear canal infection include:
Use of cotton swabs to clean the ear is a very common risk factor for ear canal infection. Cotton swabs should not be placed in the ear canal.
Symptoms of acute external otitis include pain, redness, and discharge. The discharge is unpleasant-smelling and white or yellow and drains from the ear. The ear canal may have no swelling or slight swelling, or in severe cases, it may be swollen completely closed. If the ear canal swells or fills with pus and debris, hearing is impaired. Usually, the canal is tender and hurts if the external ear (pinna or auricle) is pulled or tugged or if pressure is placed on the fold of skin and cartilage in front of the ear canal (tragus).
Fungal ear canal infection causes more intense itching than pain, and people have a feeling of fullness in the ear. Fungal infection caused by Aspergillus niger usually causes grayish black or yellow dots (called fungal conidiophores) surrounded by a cottonlike material (called fungal spores) to form in the ear canal. Fungal infection caused by Candida albicans does not cause any visible fungi to form but usually causes a thick, creamy white discharge.
Boils cause severe pain. When they rupture, a small amount of blood and pus may leak from the ear.
The doctor bases the diagnosis of ear canal infection on the symptoms and an examination of the ear canal. To a doctor looking into the ear canal through an otoscope (a device for viewing the canal and eardrum), the skin of the canal appears red and swollen and may be littered with pus and debris. An infection caused by a fungus is also diagnosed based on examination or culture (a sample of the pus and debris is grown in a laboratory to identify the microorganisms). Sometimes fungal spores can be seen in the ear canal.
Swimmer's ear may be prevented by putting drops of a solution containing half rubbing alcohol and half white vinegar (acetic acid) in the ear immediately after swimming (as long as there is no hole [perforation] in the eardrum).
Attempting to clean the canal with cotton swabs or other objects is strongly discouraged because such action interrupts the ear's normal, self-cleaning mechanism and can push debris and earwax further inward. Also, this action may cause minor damage to the delicate skin of the canal, providing a site for bacteria to infect.
To treat ear canal infection due to any cause, a doctor first removes the infected debris from the canal with suction or dry cotton wipes. After the ear canal is cleared, hearing often returns to normal.
Usually, a person with mild ear canal infection is given ear drops containing white vinegar and drops containing a corticosteroid such as hydrocortisone or dexamethasone to use several times a day for up to a week. White vinegar is helpful because bacteria do not grow as well once the normal acidity of the ear canal is restored.
With moderate or severe infection, antibiotic ear drops also are prescribed. If the ear canal is very swollen, a doctor inserts a small wick into the ear canal to allow the antibiotic/corticosteroid ear drops to penetrate. The wick is left in place for 24 to 72 hours, after which time the swelling may have gone down enough to allow the drops to go directly into the ear canal.
People who have severe acute external otitis (extends beyond the ear canal) may need to take antibiotics by mouth, such as cephalexin or ciprofloxacin.
Pain relievers such as acetaminophen or ibuprofen may help reduce pain for the first 24 to 48 hours, until the inflammation begins to subside.
To treat fungal ear canal infection, doctors thoroughly clean the ear canal and insert antifungal ear drops. Repeated cleanings and treatments may be needed. Some doctors believe that a combination of rubbing alcohol and white vinegar is particularly effective in fungal external otitis. Rubbing alcohol dries the ear canal and white vinegar creates an acidic environment that does not allow fungus to grow as well.
For both bacterial and fungal infection, people should keep the ear dry by practicing dry ear precautions (such as wearing a shower cap and avoiding swimming) until the infection clears up. A blow dryer on a low setting can also be used to reduce the humidity and moisture in the canal.
Treatment of boils depends on how advanced the infection is. In an early stage of infection, a heating pad can be applied for a short time and pain relievers, such as oxycodone with acetaminophen, can be given to help relieve pain. The heat may also help speed healing. An antibiotic is given by mouth. A boil that has come to a head is cut open (incised) to drain the pus.