Ear infections: causes, diagnosis and treatment explained

Ear infections are very common in both children and adults and can affect any part of your ear. Here we’ll look at common causes and treatments, but first, it helps to understand the anatomy of the ear. 

Ear anatomy

Your ear is divided into three sections: your outer ear, middle ear and inner ear. 

As the name suggests, your outer ear refers to outer parts of your ear, which can easily be seen. This includes the fleshy pinna, which is attached to a bowl-shaped structure called the concha. The concha runs into your ear where it meets your ear canal. Your outer ear ends where your ear canal meets your eardrum, also known as the tympanic membrane. 

Your middle ear runs from your eardrum to the structures of your inner ear. When sound travels through your outer ear, it hits your eardrum, which vibrates. Your middle ear carries these vibrations to your inner ear through three tiny bones (bony ossicles) called the malleus, incus and stapes. 

Your middle ear also contains the opening to your Eustachian tube — this tube connects your middle ear to the back of your nose, that is, your nasal-sinus cavity. It helps balance the air pressure in your middle ear and ventilate your middle ear. 

Your inner ear contains complex structures that enable you to hear and balance, specifically a spiral-shaped cochlea for hearing, and three tiny, fluid-filled tubes called the semicircular canals alongside two membranous sacs called the utricle and saccule for balance. 

Types of ear infection 

There are several different types of ear infections that affect different parts of your ear. 

Otitis externa

This refers to infection of the outer ear, specifically the ear canal, and is commonly known as swimmer’s ear. It can be caused by infection with bacteria or fungi, usually due to dirty water or water sitting in your ear canal that encourages bacteria and fungi to grow, as can happen after swimming. 

Symptoms include redness of your outer ear, itching, pus leaking from your ear, pain on touching your outer ear, muffled hearing and a full feeling in your ear. 

Otitis media

This refers to infection of the middle ear and can be acute or chronic (long-term). It is most often caused by viruses but can also be caused by bacteria, and occurs when your Eustachian tube becomes blocked.

Symptoms include ear pain, a fever, fatigue, a feeling of fullness in your ear, itching, vomiting and muffled hearing. In some cases, your eardrum may burst, leading to pus leaking out of your ear but a reduction in your ear pain. 

Vestibular neuronitis

This refers to infection of the inner ear, specifically the vestibular nerve that runs from the structures of your middle ear that control balance (semicircular canals, utricle and saccule) to your brain. Vestibular neuronitis leads to inflammation of this nerve and is usually caused by infection with a virus. 

Symptoms include sudden, intense vertigo (a spinning sensation), nausea, vomiting, balance problems, ringing in your ears (tinnitus) and vision problems, such as double vision or what you see appearing to jiggle or bounce when you move your head. 

Labyrinthitis

This also refers to infection of the inner ear, specifically the bony cavity (labyrinth) that contains the structures you need to hear (cochlea) and balance (semicircular canals, utricle and saccule). It is usually caused by infection with a virus but can also be caused by bacteria. 

Symptoms overlap with those of vestibular neuritis, namely imbalance, nausea, vomiting, vertigo, vision problems and tinnitus.

Risk factors for ear infections

Risk factors for outer ear infections include swimming and trauma to your ear eg caused by scratching your ear with long fingernails or using cotton buds to clean your ears. 

Outer ear infections are also more common in people who have eczema, allergies or diabetes, or who have immune systems that are suppressed (eg if you have HIV, or are taking immunosuppressants or having chemotherapy). 

Middle ear infections are most common in children, specifically those who have large adenoids or Eustachian tube dysfunction. 

There are no specific risk factors for inner ear infections, but they can occur when you are tired or run down.

Complications of ear infections

Ear infections, especially if left untreated, can lead to other health complications. For example, an outer ear infection can spread to your face and/or cause your ear canal to narrow. 

Middle ear infections can spread to the bony ossicles of your middle ear — if these bones are destroyed this can lead to permanent hearing loss. If the infection spreads into other bones it can cause serious, potentially life-threatening infections. For example, if it spreads to the skull, it can cause meningitis and if it spreads to the bone at the back of the ear, it can cause mastoiditis.

Inner ear infections can also lead to permanent hearing loss as well as balance problems. 

Getting a diagnosis

Ear infections are usually diagnosed based on your symptoms, medical history and an examination of the inside of your ear. In some cases, if your ear is full of debris or wax, this will need to be removed to get a clear view of your ear canal and eardrum. 

If your doctor suspects a serious infection of the bone or brain, you may need a CT scan or MRI scan. 

Treating ear infections

Treatment for an ear infection depends on its location. 

Swimmer’s ear is usually treated with topical antibiotics (drops or a cream) and suction of the pus, which is performed by a specialist doctor (ENT surgeon). 

Middle ear infections are usually treated with oral antibiotics (tablets) or, in severe cases, with intravenous (IV) antibiotics. If the eardrum has burst, it may be possible to treat a middle ear infection with topical antibiotic drops as they will be able to pass into the middle ear via the outer ear. 

If your child has persistent middle ear infections, your doctor may suggest inserting a grommet into their eardrum — this is a tiny tube that helps fluid in the middle ear drain out. 

If your middle ear infection has spread to the bones in your ear or head, you will need IV antibiotics and surgery to remove the infection. 

Inner ear infections are usually treated with antibiotics if they are caused by bacteria or antiviral medication if they are caused by a virus. In some cases, your doctor may also prescribe steroids to help reduce any inflammation. If you’re experiencing nausea and vomiting, they may also prescribe an anti-sickness medication. 

Can ear infections recur?

Children can develop frequent middle ear infections, that is, recurrent acute otitis media (AOM); however, they usually grow out of this. 

As an adult, if you have an outer ear infection, your risk of getting it again depends on whether the trigger is removed eg trauma to the ear or water persistently sitting in the outer ear. Middle ear infections in adults can also recur if the eardrum is perforated and isn’t repaired. 

Viral inner ear infections can also recur as the virus can remain inactive in your body and reactivate when you are feeling rundown or unwell. 

When to see a doctor

If you have symptoms of an ear infection, feel unwell and are not seeing any improvement in your symptoms after three days, you should see your GP. 

You should also seek urgent medical attention, if you develop sudden nausea, vomiting or hearing loss.