Mastoiditis is an infection of the bony air cells in the mastoid bone, located just behind the ear. It is rarely seen today because of the use of antibiotics to treat ear infections. This child has drainage from the ear and redness (erythema) behind the ear over the mastoid bone.
Review Date 1/24/2023
Updated by: 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.