The scientific name for earwax is cerumen. In order to understand it, we might as well know the structure of the human ear first. The human ear is divided into three parts: outer ear, middle ear and inner ear. The external ear includes auricle and external auditory canal, and there is a variant sweat gland called cerumen gland in the skin of cartilage outside the external auditory canal. It can secrete a yellowish viscous substance, which is the embryonic form of earwax. It is a complex mixture, which mainly includes cholesterol, triglycerides, alcohols and an oily substance called squalene, and also contains a small amount of substances with special functions, such as antibacterial peptides (inhibiting bacterial growth) and lysozyme (destroying bacterial cell walls). These substances are mixed and coagulated with dead cells in the skin of the external auditory canal, dust and bacteria entering the external auditory canal, forming the earwax we see every day.
Due to genetic differences, there are different cerumen gland cells in the human body, resulting in two different types of earwax: wet type and dry type. The wet type is dominant and the dry type is recessive. Wet earwax, commonly known as "oil ear", contains more fatty acids and is waxy; Dry earwax is easy to dry when exposed to air, and it is flaky and can fall off in pieces. Most Africans, Europeans and North Americans have wet earwax, so it is called earwax in English, not Earshit. Most East Asians (including China, Japanese and Koreans) have dry ear wax. In China, most people have dry ear wax, and the proportion of people with wet ear wax is slightly different between the north and the south, about 10% in the north and about 18% in the south. In addition, the transporter responsible for fatty acid secretion in cerumen gland cells and apocrine gland cells is determined by the same gene on chromosome 16. Usually, people with wet earwax are more likely to sweat and produce body odor.
By analyzing the source and composition of earwax, we can know that both dry earwax and wet earwax only contain substances that are "toxic" to bacteria, but not toxic to human body, and there is no substance that causes deafness. So far, there is no report about "poisoning or deafness caused by eating earwax by mistake". From this point of view, the statement that "ear wax is toxic" and "eating ear wax will make you dumb" is unreliable. Even if you eat earwax by mistake, don't panic.
In the past, westerners used earwax as lip balm or ointment to treat stab wounds. In the 1832 edition of American frugal housewives, it is recorded that earwax is the best painkiller for nail pricking or acupuncture, and it is also recommended to treat chapped lips with earwax. The popular saying that "earwax can relieve pain" and "earwax can treat chapped lips" may come from this. However, there is no obvious analgesic component in earwax, so the statement that earwax can relieve pain needs further study. Oily substances such as cholesterol and triglycerides contained in earwax can really moisturize dry lips and have a certain effect on relieving chapped lips. But as mentioned earlier, bacteria will be mixed in the process of earwax molding, so we don't advocate using it to moisten lips.
Earwax is acidic and has antibacterial effect; Its viscosity also has the function of protecting the skin of external auditory canal and adhering foreign bodies (such as dust and small flying insects). ); In addition, it can clean and lubricate the external auditory canal. If the earwax is cleaned too clean, it will lose its natural protective effect and destroy the environment in the ear canal. After the earwax is cleaned up, people will feel itchy because the external auditory canal is dry, so it is easy to form a habit by picking their ears reflexively. The American Academy of Otolaryngology points out that the habit of pulling out earwax is redundant and unhealthy. Ear removal will stimulate cerumen gland to secrete more earwax, damage the epidermis of external auditory canal, and even cause perforation of tympanic membrane. In most cases, the external auditory canal can be self-cleaning. First of all, the epidermal cells in the ear canal are very unique, they can migrate, and when the cells in the ear canal slowly move outward, they can bring out the earwax "by the way"; Secondly, our daily jaw movements, such as chewing, mouth opening, etc., can also help wax discharge.
Earwax does not need special cleaning or deep digging. Two thirds of the human external auditory canal does not secrete earwax, and only the auricle needs to be cleaned every day. In addition, many people mistakenly think that cotton swabs are better tools for ear plucking. In fact, cotton swabs will only push most of the earwax deep into the ear canal, forming a blockage.
If the earwax cannot be discharged normally, it will gradually agglomerate in the external auditory canal and block the external auditory canal, which is called cerumen embolism, commonly known as earwax. Excessive secretion of earwax, skin irritation of external auditory canal, frequent ear digging, external auditory canal stenosis or foreign body retention are all related to the formation of earwax.
Earwax is usually black or brown and difficult to touch. The degree and location of cerumen embolism are different, and the symptoms are also different. Incomplete obstruction of external auditory canal is mostly asymptomatic. When the external auditory canal is completely blocked, hearing loss, earache, tinnitus and dizziness often occur to varying degrees. Sometimes reflex cough is caused by cerumen embolism in the posterior wall of external auditory canal to stimulate vagus nerve. Continuous stimulation of the external auditory canal can induce skin erosion, swelling and granulation growth of the external auditory canal, which is characterized by ear pain or tightness.
Patients with embolism should not blindly dig by themselves. Because the earwax is as hard as stone at this time, forced digging may hurt the skin of the external auditory canal and even the eardrum, which is easy to cause infection. Improper ear digging will push the earwax deeper and more difficult to deal with. In case of external auditory canal cerumen embolism, please ask an otolaryngologist for professional examination and treatment.
There are still many unsolved mysteries about earwax. For example, Monel Chemical Sensory Center in the United States studied a rare genetic disease called maple syrup urine (MSUD) and found that this disease can be easily diagnosed by the smell of earwax. Compared with genetic testing, it is obviously much simpler and cheaper to dig out earwax as a test sample.