An ear infection occurs when germs, such as bacteria or viruses, invade the middle ear, leading to inflammation and fluid buildup. This condition is common in children but can affect people of all ages. Symptoms may include ear pain, difficulty hearing, and sometimes fever. There are two main types of ear infections: acute otitis media, which comes on suddenly and is often painful, and otitis media with effusion, where fluid remains in the ear after an infection has cleared. Treatment may involve pain relief, antibiotics, or in some cases, surgical procedures to drain fluid.