A middle ear infection, also known as otitis media, occurs when germs infect the space behind the eardrum. This area can become swollen and filled with fluid, leading to pain and discomfort. It is common in children but can affect people of all ages. Symptoms may include ear pain, fever, and irritability. The infection often develops after a cold or allergy, which can cause congestion in the Eustachian tube. This tube helps equalize pressure in the ear and drain fluid. Treatment may involve pain relief, antibiotics, or in some cases, surgery to drain fluid if the infection is severe or recurrent.