Otitis media is an infection in the middle ear caused by the presence of bacteria or a virus. It is often preceded by nasopharyngitis and leads to decreased hearing, ear pain and fever.

Although otitis media can occur at any age, it is more common in the pediatric age group, with around 80% of children having at least one episode of acute otitis media before school age.

All forms of otitis media result in a certain degree of hearing loss, usually transient in nature, that resolves as inflammation reduces. In cases of chronic otitis media, or with the spread of infection to the inner ear, hearing loss can be permanent.

The Eustachian tube runs from the middle ear to the back of the nose and throat, and controls the pressure inside the middle ear. When otitis media occurs, it leads the Eustachian tube to become swollen or blocked, trapping fluid in the middle ear. The propagation and development of germs through the Eustachian tube is now considered to be the main cause of the infection. The fundamental event is due to a tubal dysfunction, which occurs during an infection of the upper airways (nose and throat). Secondary events, which are more rare, can occur as germs travel through the blood or lymphatic system.

If the trapped fluid in the middle ear cannot drain away, it is easier for an infection to occur. Some common conditions that may increase the risk of otitis media occurring include:

• Allergies
• A cold or the flu
• Sinus infections
• Infected or enlarged adenoids
• Smoking
• Drinking whilst lying down (infants)

Younger children are more susceptible to a middle ear infection as the Eustachian tube is shorter and more horizontal than those in older children and adults. It is important to look out for symptoms of otitis media in young children so you can identify the right treatments to relieve any pain or high temperature. 

Chronic otitis media could also lead to a cholesteatoma, a purulent inflammation of the middle ear. Read more about symptom, causes and treatment options.