Earwax

Earwax, also known by the medical term cerumen, is a gray, orange, red or yellowish y substance secreted in the of humans and other mammals. It protects the skin of the human ear canal, assists in cleaning and lubrication, and also provides protection against, , s, and water.

Earwax consists of, hair, and the secretions of the  and s of the. Major components of earwax are, both and , alcohols, , and. Excess or compacted cerumen can press against the or block the outside ear canal or hearing aids, potentially causing.

Physiology
Cerumen is produced in the outer third of the portion of the ear canal. It is a mixture of s from s and less-viscous ones from modified. The primary components of earwax are shed layers of skin, with, on average, 60% of the earwax consisting of, 12–20% saturated and unsaturated long-chain fatty acids, alcohols, and 6–9%.

There are two distinct determined types of earwax: the wet type, which is, and the dry type, which is. While and  are more likely to have the dry type of cerumen (gray and flaky),  and  people are more likely to have the wet type (honey-brown, dark orange to dark-brown and moist). 30-50% of ns, ns and s have the dry type of cerumen. Cerumen type has been used by to track human migratory patterns, such as those of the. In Japan, wet-type earwax is more prevalent among the, in contrast to that country's majority. The wet type earwax differs biochemically from the dry type mainly by its higher concentration of and  ; for example the wet type is 50% lipid while the dry type is only 20%.

A specific has been identified that determines whether people have wet or dry earwax. The difference in cerumen type has been tracked to a single change (a ) in a gene known as "", specifically rs17822931. Dry-type individuals are for  whereas wet-type requires at least one. Wet-type earwax is associated with, which is increased by production. Researchers have conjectured that the reduction in sweat or body odor was beneficial to the ancestors of East Asians and Native Americans who are thought to have lived in cold climates.

Cleaning
Cleaning of the ear canal occurs as a result of the "conveyor belt" process of migration, aided by  movement. Cells formed in the centre of the migrate outwards from the  (at a rate comparable to that of fingernail growth) to the walls of the ear canal, and move towards the entrance of the ear canal. The cerumen in the ear canal is also carried outwards, taking with it any particulate matter that may have gathered in the canal. Jaw movement assists this process by dislodging debris attached to the walls of the ear canal, increasing the likelihood of its expulsion. Removing earwax is in the scope of practice for and  (ear, nose, and throat) doctors.

Lubrication
The lubrication provided by cerumen prevents of the  within the ear canal. The lubricative properties arise from the high content of the  produced by the sebaceous glands. In wet-type cerumen, these lipids include, , and many long-chain s and s.

Antimicrobial effects
While studies conducted up until the 1960s found little evidence supporting antibacterial activity for cerumen, more recent studies have found that cerumen has a bactericidal effect on some strains of bacteria. Cerumen has been found to reduce the viability of a wide range of bacteria, including ', ', and many variants of , sometimes by as much as 99%. The growth of two commonly present in  was also significantly inhibited by human cerumen. These antimicrobial properties are due principally to the presence of fatty acids,  and, especially, to the slight acidity of cerumen ( typically around 6.1 in normal individuals). Conversely, other research has found that cerumen can support microbial growth and some cerumen samples were found to have bacterial counts as high as 107/g cerumen.

Excess earwax
Excessive earwax may impede the passage of in the ear canal, causing, pain in the ear, itchiness, or dizziness. usually checks for visibility of the which can be blocked by excessive cerumen. Hearing aids may be associated with increased earwax impaction. It is also estimated to be the cause of 60–80% of faults. Earwax can get into a hearing aid's vents and receivers, and degrades the components inside the hearing aid due to its acidity. Excessive earwax can also cause or ringing in the ears.

Treatment
Movement of the jaw helps the ears' natural cleaning process. The discourages earwax removal, unless the excess earwax is causing problems.

While a number of methods of earwax removal are effective, their comparative merits have not been determined. A number of softeners are effective; however, if this is not sufficient, the most common method of cerumen removal is with warm water. A method is more likely to be used by s and  when the ear canal is partially occluded and the material is not adhering to the skin of the ear canal. s, on the other hand, push most of the earwax farther into the ear canal and remove only a small portion of the top layer of wax that happens to adhere to the fibers of the swab.

Softeners
This process is referred to as cerumenolysis. Topical preparations for the removal of earwax may be better than no treatment, and there may not be much difference between types, including water and olive oil. However, there were not enough studies to draw firm conclusions, and the evidence on irrigation and manual removal is equivocal.

Commercially or commonly available s include:
 * Any of a number of types of
 * (6.5%) and
 * A solution of in water, or sodium bicarbonate B.P.C. (sodium bicarbonate and glycerine)
 * Cerumol (, and )
 * Cerumenex (, s and )
 * , an emulsifying agent, an found in s
 * Mineral Oil

A cerumenolytic should be used 2–3 times daily for 3–5 days prior to the cerumen extraction.

Ear irrigation
Once the cerumen has been softened, it may be removed from the ear canal by irrigation, but the evidence on this practice is equivocal. This may be effectively accomplished with a spray type ear washer, commonly used in the medical setting or at home, with a bulb. Ear syringing techniques are described in great detail by Wilson & Roeser and Blake et al who advise pulling the external ear up and back, and aiming the nozzle of the syringe slightly upwards and backwards so that the water flows as a cascade along the roof of the canal. The irrigation solution flows out of the canal along its floor, taking wax and debris with it. The solution used to irrigate the ear canal is usually warm water, normal, sodium bicarbonate solution, or a solution of water and to help prevent secondary infection.

Patients generally prefer the irrigation solution to be warmed to body temperature, as is a common side effect of ear washing or syringing with fluids that are colder or warmer than body temperature.

Curette and cotton swabs
Earwax can be removed with an /curette, which physically dislodges the earwax and scoops it out of the ear canal. In the West, use of ear picks is usually only done by health professionals. Curetting earwax using an ear pick was common in and still practised in. Since the earwax of most Asians is of the dry type, it is extremely easily removed by light scraping with an ear pick, as it simply falls out in large pieces or dry flakes.

It is generally advised not to use s (Q-Tips or cotton buds), as doing so will likely push the wax farther down the ear canal, and if used carelessly, the. Abrasion of the ear canal, particularly after water has entered from swimming or bathing, can lead to ear infection. Also, the cotton head may fall off and become lodged in the ear canal. Therefore, cotton swabs should be used only to clean the external ear.

Ear candles and vacuuming
, also called ear coning or thermal-auricular therapy, is an practice claimed to improve general health and well-being by lighting one end of a hollow  and placing the unlit end in the. It, however, is not recommended as it is both dangerous and ineffective. Advocates say that the dark residue that shows after the procedure consists of extracted earwax, proving the efficacy of the procedure. Studies have shown that the same dark residue is left, whether or not the candle (which is made of cotton fabric and beeswax and leaves a residue after burning) is inserted into an ear. This demonstrates that the waxy residue is derived from the candle itself and not the ear. The color of the candle wax matches the light brown-colored wax of the human ear, making the distinction between the two waxes more difficult for a layperson. Because the candle itself is a hollow tube, some of the hot burnt wax could drop down inside the candle, into the ear canal, potentially injuring the eardrum. The states that ear candles are not a safe option for removing ear wax, and that no controlled studies or scientific evidence support their use for ear wax removal. Survey responses from medical specialists (otolaryngologists) in the United Kingdom reported ear injuries from ear candling including; burns, ear canal occlusions and ear drum perforations and secondary ear canal infections with temporary hearing loss. The has successfully taken several regulatory actions against the sale and distribution of ear candles since 1996, including seizing ear candle products and ordering injunctions.

Home "ear vacs" were ineffective at removing ear-wax, especially when compared to a Jobson-Horne probe.

Potential complications
A postal survey of British general practitioners found that only 19% always performed cerumen removal themselves. It is problematic as the removal of cerumen is not without risk, and physicians and nurses often have inadequate training for removal. Irrigation can be performed at home with proper equipment as long as the person is careful not to irrigate too hard. All other methods should be carried out only by individuals who have been sufficiently trained in the procedure.

The author Bull advised physicians: "After removal of wax, inspect thoroughly to make sure none remains. This advice might seem superfluous, but is frequently ignored." This was confirmed by Sharp et al., who, in a survey of 320 general practitioners, found that only 68% of doctors inspected the ear canal after syringing to check that the wax was removed. As a result, failure to remove the wax from the canal made up approximately 30% of the complications associated with the procedure. Other complications included (swimmer's ear), which involves inflammation or bacterial infection of the external acoustic meatus, as well as, , , and perforation of the ear drum. Based on this study, a rate of major complications in 1/1000 ears syringed was suggested.

Claims arising from ear syringing mishaps account for about 25% of the total claims received by New Zealand's ENT Medical Misadventure Committee. While high, this is not surprising, as ear syringing is an extremely common procedure. Grossan suggested that approximately 150,000 ears are irrigated each week in the United States, and about 40,000 per week in the United Kingdom. Extrapolating from data obtained in Edinburgh, Sharp et al. place this figure much higher, estimating that approximately 7000 ears are syringed per 100,000 population per annum. In the New Zealand claims mentioned above, perforation of the tympanic membrane was by far the most common injury resulting in significant disability.