Chronic otitis media (middle ear infection) is an acute bacterial infection, which often blocks your ear drums. It is a bacterial or viral infection in the middle ear space, which also affects the mastoid bone (on the back side of the ear). Mastoid bone contains air holes which drain out the middle year. An infection can commonly occur in cold weather conditions, or if water enters the middle year. Any other ear infection can also cause this infection. It is a painful condition, as it causes swelling and fluid accumulation during the time of infection. In addition, any risk of mastoid bone infection can lead to serious health disorders such as skull infection, or in severe cases, pus in the brain.