Ear infections include acute otitis media, or AOM, an inflammation of the ear, characterized by pain, fever, and tugging at the ear and otitis media with effusion, OME, which refers to the accumulation of fluid in the middle ear without any apparent signs of infection. According to the American Academy of Pediatrics, AOM is the most common illness in children for which antibiotics are prescribed in the United States and about 90 precent of children have OME at some time before school age, most often between ages 6 months and 4 years.
Causative Organisms
Children are more prone to ear infections than adults because their immune systems are underdeveloped. The University of Maryland Medical Center reports that Streptococcus pneumoniae is the most common bacteria that is responsible for about 40 to 80 percent of childhood ear infection cases in the U.S. Haemophilus influenzae is the next most common isolate and is responsible for 20 to 30 percent of acute infections. Moraxellacatarrhalis is responsible for 10 to 20 percent of infections. Other common causes include Streptococcus pyogenes and Staphylococcus aureus.
Viruses, such as respiratory syncytial virus and influenza, can cause upper respiratory tract infections. University of Maryland Medical Center states that nearly one-third of infants and toddlers with upper respiratory infections go on to develop ear infections.
Other viruses, especially those that cause colds such as rhinovirus, do not directly cause ear infections but set the scene for a bacterial infection. When cold occurs, the virus can cause inflammation and thickening of air passages, which can lead to the build-up of fluids in the ear. These fluids become a breeding ground for bacteria and can lead to subsequent infection.
Anatomical Causes
The Eustachian tube is a small passageway that connects the upper part of the throat to the middle ear. According to the National Institute on Deafness and Other Communication Disorders, this tube is shorter and straighter in the child than in the adult and is one of the main factors that puts children at a higher risk of ear infections.
Another factor that makes children more susceptible to ear infections are adenoids, which are masses of immune cells positioned in the back of the upper part of the throat. Adenoids are larger in children than in adults and interfere with the Eustachian tube opening, thereby, creating the perfect environment for multiplication of bacteria.
Inborn structural abnormalities, such as cleft palate and relatively short Eustachian tubes, increase the risk of ear infections. Children with Down syndrome or fetal alcohol syndrome may also be at increased risk due to anatomical abnormalities.
Other Risk Factors
Apart from colds and sinus infections, allergies, tobacco smoke and excess mucus and saliva produced during teething can cause ear infections in children. Medline Plus, a website of the National Institutes of Health, also states that ear infections in children may occur due to excessive use of "sippy" cups, cold weather or reduced immunity. Also, contrary to popular opinion, getting water in the ears will not cause an acute ear infection, unless the eardrum has a hole from a previous episode.
