Outer ear infection

Swimmer's ear symptoms are usually mild at first, but they may get worse if your infection isn't treated or spreads. Doctors often classify swimmer's ear according to mild, moderate and advanced stages of progression.

Mild signs and symptoms

• Itching in your ear canal
• Slight redness inside your ear
• Mild discomfort that's made worse by pulling on your outer ear (pinna, or auricle) or pushing on the little "bump" (tragus) in front of your ear
• Some drainage of clear, odorless fluid

Moderate progression

• More intense itching
• Increasing pain
• More extensive redness in your ear
• Excessive fluid drainage
• Discharge of pus
• Feeling of fullness inside your ear and partial blockage of your ear canal by swelling, fluid and debris
• Decreased or muffled hearing

Advanced progression

• Severe pain that may radiate to your face, neck or side of your head
• Complete blockage of your ear canal
• Redness or swelling of your outer ear
• Swelling in the lymph nodes in your neck
• Fever

Swimmer's ear is an infection that's usually caused by bacteria commonly found in water and soil. Infections caused by a fungus or a virus are less common.

Your ear's natural defenses

Your outer ear canals have natural defenses that help keep them clean and prevent infection. Protective features include:

• Glands that secrete a waxy substance (cerumen). These secretions form a thin, water-repellent film on the skin inside your ear. Cerumen is also slightly acidic, which helps further discourage bacterial growth. In addition, cerumen collects dirt, dead skin cells and other debris and helps move these particles out of your ear. The waxy clump that results is the familiar earwax you find at the opening of your ear canal.
• Downward slope of your ear canal. Your ear canal slopes down slightly from your middle ear to your outer ear, helping water drain out.

How the infection occurs

If you have swimmer's ear, your natural defenses have been overwhelmed. Conditions that can weaken your ear's defenses and promote bacterial growth include:

• Excess moisture in your ear. Heavy perspiration, prolonged humid weather or water that remains in your ear after swimming can create a favorable environment for bacteria.
• Scratches or abrasions in your ear canal. Cleaning your ear with a cotton swab or hairpin, scratching inside your ear with a finger, or wearing headphones or hearing aids can cause small breaks in the skin that allow bacteria to grow.
• Sensitivity reactions. Hair products or jewelry can cause allergies and skin conditions that promote infection.

Factors that may increase your risk of swimmer's ear include:

• Swimming
• Swimming in water with elevated bacteria levels, such as a lake rather than a well-maintained pool
• A narrow ear canal — for example, in a child — that can more easily trap water
• Aggressive cleaning of the ear canal with cotton swabs or other objects
• Use of certain devices, such as headphones or a hearing aid
• Skin allergies or irritation from jewelry, hair spray or hair dyes

Swimmer's ear usually isn't serious if treated promptly, but complications can occur.

• Temporary hearing loss. You may experience muffled hearing that usually gets better after the infection clears up.
• Long-term infection (chronic otitis externa). An outer ear infection is usually considered chronic if signs and symptoms persist for more than three months. Chronic infections are more common if there are conditions that make treatment difficult, such as a rare strain of bacteria, an allergic skin reaction, an allergic reaction to antibiotic eardrops, or a combination of a bacterial and fungal infection.
• Deep tissue infection (cellulitis). Rarely, swimmer's ear may result in the spread of infection into deep layers and connective tissues of the skin.
• Bone and cartilage damage (necrotizing otitis externa). An outer ear infection that spreads can cause inflammation and damage to the skin and cartilage of the outer ear and bones of the lower part of the skull, causing increasingly severe pain. Older adults, people with diabetes or people with weakened immune systems are at increased risk of this complication. Necrotizing otitis externa is also known as malignant otitis externa, but it's not a cancer.
• More widespread infection. If swimmer's ear develops into necrotizing otitis externa, the infection may spread and affect other parts of your body, such as the brain or nearby nerves. This rare complication can be life-threatening.