An ear infection occurs when bacteria or viruses infect parts of the ear, leading to inflammation and discomfort. It can affect the outer ear, middle ear, or inner ear, with the middle ear being the most commonly involved. Ear infections are especially frequent in children but can affect people of all ages. They often develop after a cold, sinus infection, or allergies that cause fluid buildup behind the eardrum.

Symptoms depend on the part of the ear affected but commonly include ear pain, pressure, reduced hearing, and sometimes fluid drainage. In children, signs may also include irritability, tugging at the ear, or difficulty sleeping. Some people may experience a feeling of fullness in the ear or mild dizziness, particularly if the inner ear is involved.

Middle ear infections usually occur when fluid becomes trapped behind the eardrum, creating an environment where bacteria or viruses can multiply. Outer ear infections, also known as swimmer’s ear, develop when moisture or damage to the ear canal allows bacteria to grow. Inner ear infections are less common but can cause balance problems and vertigo.