Mastoiditis is an infection of the mastoid bone, the bony prominence behind the ear, and usually develops after untreated or inadequately treated otitis media. Symptoms of mastoiditis include ear pain, swelling and tenderness behind the ear, fever, headache, hearing loss and sometimes pus discharge from the ear. Left untreated, the infection can lead to serious complications such as brain abscess, meningitis and hearing loss. Treatment of mastoiditis usually involves intravenous antibiotics and, in some cases, surgery (removal of infected tissue from the mastoid bone). Early diagnosis and treatment are of great importance for the prognosis of the disease.