The use of cotton swabs in the ear canal is associated with no medical benefits and poses definite medical risks. Cerumen (ear wax) is a naturally occurring, normally extruded product of the external auditory canal that protects the skin inside the ear, serves beneficial lubrication and cleaning functions, and provides some protection from bacteria, fungi, insects, and water. A 2004 study found that the "[u]se of a cotton-tip applicator to clean the ear seems to be the leading cause of otitis externa in children and should be avoided. " Attempts to remove cerumen with cotton swabs may result in cerumen impaction, a buildup or blockage of cerumen in the ear canal, which can cause pain, hearing problems, ringing in the ear, or dizziness, and may require medical treatment to resolve. The use of cotton swabs in the ear canal is one of the most common causes of perforated eardrum, a condition which sometimes requires surgery to correct. For these reasons, the American Academy of Family Physicians, among many other professional medical associations, recommends never placing cotton swabs in the ear canal. In the US between 1990 and 2010, an estimated 263 338 children went to hospital emergency rooms for cotton swab injuries.