Ear infection, medically known as otitis, is an inflammation or infection affecting the outer, middle, or inner ear, most commonly the middle ear (otitis media). It often develops after a cold or upper respiratory infection when fluid becomes trapped behind the eardrum, allowing bacteria or viruses to grow. Symptoms may include ear pain, pressure, reduced hearing, fever, irritability in children, and sometimes fluid drainage from the ear. Outer ear infections (otitis externa), sometimes called “swimmer’s ear,” typically cause pain when the ear is touched and may result from moisture or minor injury to the ear canal. Treatment depends on the type and severity and may include pain relief, antibiotics for bacterial infections, or supportive care, with prompt medical evaluation recommended for severe or persistent symptoms.