What are outer ear infections?

Outer ear infections, or otitis externa, affect the skin lining the ear canal, between the opening of the ear and the eardrum. This causes inflammation and swelling of this region, which results in pain, itching in the ear, temporary hearing loss and discharge of a smelly yellow-green pus.

Outer ear infections are also known as 'swimmer's ear' because they tend to develop after swimming, showering, or other activities that cause the ears to become waterlogged. Soggy skin in your ear canal provides an ideal environment for bacteria and fungi to grow, which can lead to an infection.

Typical inflammation and swelling of the ear canal due to an outer ear infection. 

The ear

The ear is made up of three main parts: the outer ear, middle ear and inner ear. Outer ear infections cause inflammation and swelling of the outer ear canal, which is located between the opening of the ear and the eardrum.

Bacteria

Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.

Fungi

An organism from the fungi kingdom, which is a separate group to plants or animals, and includes yeasts, moulds and mushrooms. Fungi feed on organic matter.

Infections

Entry into the body of microorganisms that can reproduce and cause disease.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Inner ear

The innermost portion of the ear embedded in the temporal bone, including the semicircular canals and the cochlea.

Middle ear

The air-filled central space of the ear, between the eardrum and the inner ear.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Pus

A bodily fluid that is the result of an inflammatory response at an infection site. Its colour can range from whitish to yellow to green, depending on the composition. Pus is mainly composed of dead bacteria, white blood cells and cellular debris.

Eardrum

The thin membrane between the external and middle ear that converts soundwaves into vibrations, which are then transmitted to the inner ear.

Causes

Outer ear infections are usually caused by an infection with bacteria or fungus, or sometimes both. As the ear canal is warm, dark and prone to collecting moisture, it provides an ideal environment for these germs to grow.

In most cases, the infection is caused by Pseudomonas aeruginosa or Staphylococcus aureus bacteria. Other, rarer cases, are caused by the Aspergillus and Candida families of fungus. An infection is most commonly triggered by swimming or other activities that allow water to pool in the ears.

Alternatively, an outer ear infection can also occur when a middle ear infection spreads from the other side of the eardrum into the outer ear canal.  For this to occur, there must generally be a hole in the eardrum (perforated eardrum).

In some cases, damage to the ear canal alone may be enough to cause an outer ear infection. Factors that may cause damage include pushing foreign objects into the ears, irritation from hair products, or a skin condition such as eczema, psoriasis or acne.

Outer ear infections may develop quickly, or build up over time from cycles of itchiness, scratching and further irritation that leave the skin dry and cracked.

Bacteria

Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.

Fungus

An organism from the fungi kingdom, which is a separate group to plants or animals, and includes yeasts, moulds and mushrooms. Fungi feed on organic matter.

Infections

Entry into the body of microorganisms that can reproduce and cause disease.

Middle ear

The air-filled central space of the ear, between the eardrum and the inner ear.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Eardrum

The thin membrane between the external and middle ear that converts soundwaves into vibrations, which are then transmitted to the inner ear.

Risk factors

Risk factors that can increase your chances of developing outer ear infections include:

  • Swimming, particularly in water that is dirty or stagnant;
  • Exposure to hot, humid climates;
  • Frequent use of earphones or hearing aids;
  • Cleaning the ears with cotton buds;
  • Ear abnormalities, such as particularly narrow or hairy ear canals;
  • Skin irritation or allergy from exposure to jewellery, hair products or soaps;
  • An underlying medical condition that causes skin dryness (such as eczema), or increases the risk of skin infections (such as diabetes), and;
  • Rarely, tumours such as squamous cell or basal carcinoma in the skin of the outer ear.

Allergy

A harmful, hypersensitive immune reaction to usually innocuous environmental substances.

Diabetes

A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterised by high blood sugar levels. Also known as diabetes mellitus.

Infections

Entry into the body of microorganisms that can reproduce and cause disease.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Signs and symptoms

Common symptoms of an outer ear infection include:

  • Mild to severe ear pain;
  • An itchy ear;
  • Temporary hearing loss;
  • Yellow-green discharge from the ear;
  • A feeling of fullness in the ear, and;
  • Swollen neck glands.

Outer ear infections typically occur in one ear at a time. Symptoms often appear within a few days of swimming and may start with itchiness, followed by ear pain. This pain may feel worse while chewing, or with movement of the visible, fleshy part of the ear (pinna).

Glands

Any organ of the body that secretes substances, such as hormones or enzymes, that are used by other parts of the body.

Infection

Entry into the body of microorganisms that can reproduce and cause disease.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Methods for diagnosis

Your doctor will typically diagnose an outer ear infection from the symptoms and by examining your ear with an instrument called an otoscope. From this examination, your doctor may be able to see:

  • Discharge on the walls of the ear canal;
  • Redness, scaling or peeling skin in the ear canal, and;
  • Inflammation and swelling of the eardrum.

An otoscope is used to examine the ear. 

In cases where there is discharge from the ear, your doctor may swab the area to help identify whether the cause of infection is a bacteria or fungus. If more tests are required, you may be referred to an ear, nose and throat (ENT) specialist.

Bacteria

Microscopic, single-celled organisms with DNA but no definite nucleus. Bacteria are the cause of many human diseases.

Fungus

An organism from the fungi kingdom, which is a separate group to plants or animals, and includes yeasts, moulds and mushrooms. Fungi feed on organic matter.

Infection

Entry into the body of microorganisms that can reproduce and cause disease.

Inflammation

A body’s protective immune response to injury or infection. The accumulation of fluid, cells and proteins at the site of an infection or physical injury, resulting in swelling, heat, redness, pain and loss of function.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Eardrum

The thin membrane between the external and middle ear that converts soundwaves into vibrations, which are then transmitted to the inner ear.

Types of treatment

Treatments for a outer ear infection differ from person to person, depending on the cause and severity of infection. In general though, the aim is to reduce pain, clear the infection and keep the ear canal clean and dry. Generally, an outer ear infection will clear up on its own within a few weeks. In cases where treatments are used, these include: 

Self care

To relieve the pain of an outer ear infection at home, you may wish to apply a warm compress to the affected ear. Alternatively, pain-relief medications such as paracetamol or ibuprofen are available without a prescription.

In cases where there is discharge present, cleaning the outer ear gently with cotton wool may help to keep the area clean. However, leaving cotton wool in the ear or cleaning the ear with any kind of foreign object isn't recommended. This can damage the skin and push debris further into the ear.

Medication

If you seek treatment for an outer ear infection, your doctor will most likely prescribe an ear-drop medication containing:

  • Acetic acid, to dry and clean the ear;
  • An antibiotic (e.g. framycetin or neomycin) to fight a bacterial infection;
  • An antifungal (e.g. nystatin or clioquinol) to fight a fungal infection, or;
  • Antibiotics combined with a corticosteroid (e.g. framycetin and gramicidin with dexamethasone) to fight a bacterial infection and reduce swelling.

Consulting your doctor on how to correctly apply ear-drop medication is recommended to ensure the best result. Outer ear infections usually clear completely within about 7-10 days of starting treatment, although you will most likely notice improvements within the first three days.

For infections that are severe or ongoing, your doctor may prescribe an oral antibiotic, such as fluxcloxacillin. If pain is severe, a stronger pain-relief medication, such as codeine, may be an option.

Specialist treatment

In severe cases, your doctor may treat outer ear infections as follows:

Ear wicks

If swelling in the ear canal makes it hard to apply ear drops at home, your doctor may insert a small absorbent plug into the ear. Called a wick, this plug absorbs the ear drops and helps to spread them throughout the entire length of the ear canal. The wick is then removed after the infection has cleared.

Ear wicks, with absorbed eardrops, can be used to treat an outer ear infection. 

Suction cleaning

As cleaning the ear canal at home can cause skin damage, your doctor may carefully remove discharge for you using a suction device and cotton wool on the end of a special stick. In some cases, water may also be gently squirted into the ear with a syringe to help the cleaning process.

Antibiotic

Chemical substances that kill or suppress the growth of bacteria.

Antifungal

A medication that kills fungi or inhibits their growth.

Corticosteroid

A medication that resembles the cortisol hormone produced in the brain. It is used as an anti-inflammatory medication.

Infection

Entry into the body of microorganisms that can reproduce and cause disease.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Codeine

A type of pain-relief medication, similar to morphine.

Potential complications

Complications associated with outer ear infections are uncommon, but can include:

  • Ongoing or repeated infection of the ear canal (chronic otitis externa);
  • Formation of scar tissue, leading to a narrowing of the ear canal and hearing loss;
  • An inflamed or burst eardrum;
  • Formation of a pus-filled lump (abscess) in or around the ear;
  • Spread of infection to the face or deeper layers of skin (cellulitis), and;
  • Spread of infection to cartilage or bones within the skull (malignant otitis externa).

Cartilage

A tough, flexible connective tissue found in various parts of the body including the joints and larynx.

Infections

Entry into the body of microorganisms that can reproduce and cause disease.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Pus

A bodily fluid that is the result of an inflammatory response at an infection site. Its colour can range from whitish to yellow to green, depending on the composition. Pus is mainly composed of dead bacteria, white blood cells and cellular debris.

Eardrum

The thin membrane between the external and middle ear that converts soundwaves into vibrations, which are then transmitted to the inner ear.

Prognosis

In most cases, outer ear infections only cause mild discomfort and clear up in about 7-10 days when treated with ear-drop medications or cleaned by your doctor. However, the infections can also last for weeks at a time or keep recurring, particularly if left untreated or if the infection is caused by a multi-resistant organism. Complications usually only occur in people who have a weakened immune system or an underlying medical condition.

Immune system

The organs and cells involved in protecting the body against infection.

Infections

Entry into the body of microorganisms that can reproduce and cause disease.

Organism

A form of life. It includes single-cell forms such as bacteria and more complex forms such as fungi, plants and animals.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.

Prevention

Outer ear infections may be prevented by wearing earplugs or a cap while swimming or showering, avoiding dirty water and always drying wet ears thoroughly. Cleaning only the outer, fleshy part of the ear, rather than using any kind of foreign object in the ear, is also recommended.

If outer ear infections keep recurring, you may wish to speak to your doctor about using an ear-drop medication for prevention, rather than just as a treatment. Seeking treatment for any underlying allergies or skin conditions may also help to prevent the development of an outer ear infection.

Allergies

A harmful, hypersensitive immune reaction to usually innocuous environmental substances.

Infections

Entry into the body of microorganisms that can reproduce and cause disease.

Outer ear

The external part of the ear, made of cartilage and bone, leading to the eardrum.