• Health & Wellness

    What Causes an Outer Ear Infection and How Is It Treated?

Medically reviewed by Brian A. Neff, M.D.

December 09, 2011

Dear Mayo Clinic:

My ear has been itching for a few days and it hurts to put in my hearing aid. My doctor said it's an outer ear infection. What caused this and is there any way to prevent it from happening in the future?

An outer ear infection, called external otitis or otitis externa, is most often caused by a bacterial infection that invades the layer of skin lining the ear canal. Prompt treatment clears up most outer ear infections.

The outer ear canal has natural defenses that prevent infection. The canal slopes downward, allowing water to drain out. Glands in the canal secrete earwax (cerumen) that forms a water-repellent film. Earwax discourages bacterial growth. It also collects dead skin cells, dirt and debris and helps move them out of the ear.

External otitis can occur at any age. A viral or fungal infection may be the cause, but most commonly it's a bacterial infection due to:

Moisture — A moist environment favors bacterial growth. If water remains in your ear after swimming or bathing, the normal earwax and skin barrier can break down. External otitis is often called "swimmer's ear." Increased moisture in the ear canal may also be caused by prolonged exposure to humidity.

Scratches or irritation — The thin ear canal skin may be damaged by scratching inside your ear with a finger, or by trying to remove wax with a foreign object such as a cotton swab, hairpin or paper clip. Small breaks in the skin may occur with use of earphones or hearing aids.

Sensitivity reactions — Reactions to hair products or jewelry can cause allergies or skin conditions that promote infection.

Signs and symptoms of an outer ear infection may include itching in the ear canal; ear pain or pain when touching or tugging on the outer ear; clear fluid or pus leaking from the ear; a feeling of fullness in the ear; and decreased or muffled hearing.

A more severe and aggressive infection (necrotizing otitis externa) is a dangerous complication of an outer ear infection. The infection spreads into nearby tissues, including cartilage and bone in the skull. It may cause increasingly severe and deep-seated pain. It's more common in older adults, people who have diabetes and those who have weakened immune systems. Untreated, it can be life-threatening. Treatment is weeks to months of intravenous and then oral antibiotics.

It's important to see your doctor if you have ear pain or discomfort. If you have severe pain or a fever, contact your doctor immediately or seek emergency care.

Acute outer ear infection treatment generally starts with cleaning debris and discharge from the outer ear canal so that eardrops can reach infected areas. Depending on the type and severity of your infection, eardrops with some combination of the following are often prescribed:

  • An acidic solution to reset the ear's antibacterial environment
  • An antibiotic to fight bacteria
  • Steroid to reduce inflammation
  • An antifungal drug, if a fungal infection is thought to be present

Although most outer ear infections don't require oral antibiotics, your doctor may prescribe them if your infection is more advanced or isn't responding to eardrops.

If you have diabetes, a weakened immune system or have had radiation treatment affecting the ear, oral antibiotics may be prescribed along with eardrops.

To avoid a future outer ear infection, take a break from wearing your hearing aids, if possible, to give moisture buildup a chance to dry. Protect your ears with cotton balls when using products such as hair sprays and dyes. For persistent itching, see your doctor. Some skin conditions affect the external canal and can be treated topically.

It's also important that you carefully dry your ears after swimming or bathing. If you know you don't have a punctured eardrum, consider a nonprescription solution or homemade preventive eardrops to aid drying before and after swimming. Put several drops of a 50-50 mixture of white vinegar and rubbing alcohol into each ear and then let the mixture drain out.

Finally, don't use foreign objects to remove earwax or scratch an itch in your ear canal. Mineral oil applied to the opening of the canal is safer than scratching the inside.

— Brian A. Neff, M.D., Otorhinolaryngology, Mayo Clinic, Rochester, Minn.