Otitis

Otitis is a term for an infection or inflammation of the ear.

Otitis can affect the inner or outer parts of the ear. The condition can be:

• An acute ear infection -- Starts suddenly and lasts for a short period of time. It is often painful.
• A chronic ear infection -- Occurs when the ear infection does not go away or keeps coming back. It may cause long-term damage to the ear.

Based on location, otitis can be:

• Otitis externa (swimmer's ear) -- Involves the outer ear and ear canal. A more severe form can spread into the bones and cartilage around the ear.
• Otitis media (ear infection) -- Involves the middle ear, which is located just behind the eardrum.
• Otitis media with effusion -- Occurs when there is thick or sticky fluid behind the eardrum in the middle ear, but there is no ear infection. Also called serous otitis media.

Matlock AG, Pfaff JA. Otolaryngology. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 58.

Player B. Otitis media. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 680.

Tahtinen PA, Pelton SI. Otitis externa, otitis media, and mastoiditis. In: Blaser MJ, Cohen JI, Holland SM, et al, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 10th ed. Philadelphia, PA: Elsevier; 2026:chap 63.

Weinreich HM, Martin E, Santos F. Chronic otitis media, mastoiditis, and petrositis. In: Francis HW, Haughey BH, Hillel AT, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 8th ed. Philadelphia, PA: Elsevier; 2026:chap 139.

Last reviewed on: 7/16/2024

Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.