Causes of Ear Infections The causes of ear infections depend on the type of infection, but they are usually linked to bacteria, viruses, or fungi entering the ear and triggering inflammation. Most ear infections begin when another illness, such as a cold, flu, or allergy, causes congestion and swelling in the nasal passages, throat, and eustachian tubes. The eustachian tubes help ventilate the middle ear and drain fluids into the throat. When they become blocked, fluid builds up behind the eardrum, creating a warm and moist environment where germs can grow. This trapped fluid is a key factor in the development of middle ear infections. Bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis are common culprits in middle ear infections. Viruses like the flu or respiratory syncytial virus (RSV) can also trigger infections by causing inflammation and reducing the body’s ability to fight off bacteria. Outer ear infections are often caused by water entering the ear canal and creating a breeding ground for bacteria. This is especially common in swimmers or people who clean their ears with cotton buds, which can scratch the skin and introduce germs. Fungal infections may also occur in tropical or humid environments, including some regions of South Africa. Inner ear infections are usually the result of viral infections, such as those linked to measles, mumps, or influenza. These infections can affect the cochlea and vestibular system, leading to dizziness, nausea, and temporary or permanent hearing loss. Several risk factors increase the likelihood of developing ear infections: Young age (especially between 6 months and 2 years) Bottle-feeding while lying down Exposure to tobacco smoke or air pollution Seasonal colds and allergies Poor hygiene or recurrent upper respiratory infections A family history of frequent ear infections Causes of Ear Infections In South African communities where healthcare access is limited, environmental factors like overcrowding, poor air quality, and under-vaccination can worsen the spread of infections. Children in these settings may also lack early intervention, increasing the risk of chronic otitis media and associated hearing problems. It’s also important to consider structural causes, such as cleft palate, which can affect the function of the eustachian tubes. In adults, ear infections may be linked to underlying skin conditions (like eczema in the ear canal), the use of hearing aids or earbuds, or water-based occupations. Understanding the causes of ear infections allows for targeted prevention, such as vaccinations, good hygiene, and reducing exposure to irritants. For recurring infections, doctors may suggest inserting grommets (ear tubes) to help with fluid drainage and reduce the risk of complications. [Next: Symptoms of Ear Infections →]