Are mites really that terrible? The worm mite, commonly known as the hair follicle mite, is a small mite, a genus of worm mite in the family of worm mites, and there are about 134 known species of worm mites. The former is mostly parasitic in human skin follicles, the latter is mostly parasitic in sebaceous glands, which can cause worm mite dermatosis, clinically used to be called “follicular worm dermatitis”, due to the different forms of the two mites, different parasitic sites, causing different clinical symptoms. The prevalent sites are the face, nose, cheeks, and forehead, but can also be seen on other parts of the skin. The skin lesions often show diffuse erythema, papules, desquamation, capillary dilation, hair loss and other symptoms. The current status of human crepuscular mite infection is worldwide, with foreign scholars reporting a population infection rate of 27% to 100% and domestic scholars reporting an infection rate of 0.8% to 81.0%. Since the detection rate of crepuscular mites is influenced by various factors such as examination methods, time and environment, the reported infection rate varies greatly from place to place. Differences in infection rates between men and women were reported differently from place to place. The results of Liu Yisu et al. showed that the prevalence of crepuscular mite infection in men and women was basically the same, with no significant difference, indicating that crepuscular mite infection is not related to gender, and that the prevalence of crepuscular mite infection is relatively stable in a certain population range, with most of the infected individuals being infected with simple follicular crepuscular mites and occasionally mixed infections. It has also been reported that the prevalence of mite infection in adults today has reached 97%. Animal studies have shown that worm mites are mainly parasitic in various domestic and wild mammals such as dogs, pigs, cats, cattle, sheep, rabbits, and rats. In order to clarify the transmission route of worm mites, inoculation of human worm mites into white rabbits has been successful, which further proves that humans and animals can cross-infect each other. From the epidemiological survey data of human wormy mite disease, wormy mite disease is an extremely common skin disease, seriously affecting skin health, is also the nemesis of beauty, should be concerned by the general public, especially public health, dermatology and beauty industry should pay sufficient attention to the development of effective preventive and control measures. 2. Parasitic sites and pathological changes of human crepuscular mites (1) Parasitic sites. Hair follicle mites are mainly parasitic in human hair follicles and are a conditionally pathogenic parasite. They are parasitic not only on the sebaceous face, but also on the eyelashes and body parts, causing a variety of clinical symptoms under suitable parasitic and pathogenic conditions. Follicular mites are mainly parasitic in hair follicles, with the head of the insect facing directly into the follicle and parasitizing near the hair shaft, with the head facing in and the tail facing out in an inverted manner. One to three mites can be found in a hair follicle, causing enlargement of the hair follicle and the follicle opening with inflammatory cell infiltration around it. Sebaceous mites are mainly found in the ducts of the sebaceous glands and can cause obstruction of the sebaceous ducts. The sebaceous mite mainly parasitizes the sebaceous glands and the ducts of the sebaceous glands, and it causes obstruction of the openings of the sebaceous glands, which are surrounded by a large number of neutrophil infiltrates and form microabscesses. Both mites prefer to reside in the hair follicles of the more developed sebaceous glands of the body, including the nose, periocular area, lips, forehead, scalp and even the nipples, chest and neck, causing inflammation of the hair follicles and sebaceous glands. (2) Pathological changes. The human body is not immune to helminth infections and can be infected by different age, ethnicity and gender. Human helminths are parasitic in the deep hair follicles and sebaceous glands and are permanent parasites in the human body. Due to mechanical stimulation of the insects and chemical stimulation of the insect excretion, the parasitic site can cause enlargement of hair follicles, vasodilatation, infiltration of surrounding cells, proliferation of fibrous tissue, pathological changes in skin tissues and different degrees of inflammatory reactions, resulting in various damages such as erythema, papules, pustules and nodules. In the enlarged hair follicles and hyperplastic sebaceous glands of rosacea patients with facial lesions, a large number of adult worm mites, worm eggs and eggs could be examined, and there were different degrees of inflammatory reactions around the histopathological changes of the skin, which showed that parasitism of worm mites was closely related to histopathological changes of the skin and was one of the important causative factors of rosacea. The longer the parasitic time of the mite, the longer the duration of rosacea and the more severe the disease, causing different degrees of pathological changes in the host skin tissue and significantly increased damage, closely related to the enlargement of skin tissue follicles, sebaceous gland hyperplasia and inflammatory reactions. However, most infected patients have no clinical symptoms, and only a few have clinical symptoms due to histopathological changes in the skin, indicating that the etiology of rosacea is not caused by mite parasitism alone, but whether it can cause clinical symptoms due to histopathological changes in the skin depends on the differences in immune function and whether there are secondary However, the ability to cause histopathological changes in the skin and clinical symptoms depends on the differences in immune function and the presence of secondary pathogenic factors such as infection with pathogenic microorganisms. Hair follicle mites are more common and more pathogenic than sebaceous mites. Some scholars have shown that human crepuscular mite infection can cause local skin hyperkeratosis or hyperkeratosis, capillary proliferation and expansion in the dermis, resulting in skin roughness and affecting the appearance, and can also cause acne, seborrheic dermatitis, folliculitis, rosacea, and other skin diseases. Hair follicle mites have been found to parasitize mainly the roots of hair follicles in skin tissue sections and partially in the peripheral parts of hair follicles, causing inflammatory reactions in these parts of the tissue. Sebaceous mites are often found in the ductal and glandular parts of sebaceous glands. Experimental and clinical observations have shown that changes such as pocket expansion of hair follicles, formation of keratin plugs, and enlargement of pores are the main causes of skin roughness; the enlargement of hair follicles and the entry and exit activities of sebaceous mites can easily bring in purulent bacteria, which can lead to secondary follicles or sebaceous gland inflammation and boils, suggesting that infection by sebaceous mites is closely related to the development of certain human skin diseases. 3, the pathogenic situation of human crepuscular mites The infection rate of human crepuscular mites in China is high, and there is still a debate about whether crepuscular mites are pathogenic or not for many years. Follicular mites are mainly parasitic in the eyelashes and various parts of the body, and can cause a variety of skin damage under suitable parasitic and pathogenic conditions, with lesions often occurring in the nasal face where sebaceous glands secrete more. In the early stages of the disease, there are scattered or diffuse rosy erythema, papules and mild capillary spread on the nasal cheeks. In the middle stage: papules, papules, pustules, desquamation, and marked vascular dilatation of varying sizes are seen. Late stage: hyperpigmentation, capillary dilated tissue proliferation. Follicular mites also have various clinical manifestations, such as seborrheic alopecia-like, pityriasis simplex-like, blepharitis-like, whiskers-like, acne-like, and seborrheic dermatitis-like lesions. In severe cases, due to tissue hyperplasia, nasal nodules of different sizes can be formed on the nose, and in late stages, the nose can become hypertrophic and deformed, forming nasal redundancy, accompanied by dryness of the nasal mucosa and dyspnea. Foreign scholars report that the infection rate of the population is 27% to 100%, and domestic report that the infection rate is between 0.8% and 81.0%. Such a high infection rate indicates that many healthy people have worm mites on their skin, but not necessarily cause disease, if they all cause disease, then most of us are going to get trichinosis. Although trichinosis dermatitis is documented in professional books, this diagnosis is rarely given in actual clinical work. The most common facial skin diseases are acne (pimples), seborrheic dermatitis, rosacea, and facial (allergic) dermatitis. Each of these diseases has its own etiology. For example, acne is caused by increased male hormones (also found in women), excessive secretion of sebaceous glands, clogged pores and bacterial infections; seborrheic dermatitis is caused by excessive sebum production; facial dermatitis is mostly caused by allergic factors (such as cosmetics); rosacea has an unknown etiology and may be related to diet, gastrointestinal dysfunction and psychological factors. Although some people found follicular worm mite in the skin lesions of rosacea and thought it was the pathogenic factor of acute rosacea, the number of infected follicles in rosacea and the number of parasites of this mite in each follicle were not more than the control group without rosacea, and after treatment with sulfur ointment, rosacea improved while follicular worm mite did not decrease, according to Tang Hongsan. Some people also believe that follicular mite parasitism is perfectly normal and nothing special like the presence of bacteria on our skin, but follicular mites do cause a disease called follicular dermatitis. vollmer et al. suggested that helminth infection may be the cause of facial acne. It is generally believed that helminths are related to acne, rosacea, and other skin damage. Follicular worm mites parasitize humans, and individual differences in hosts cause humans to show different responses to follicular worm mite infection, i.e., some people can show clinical symptoms while others do not show any symptoms. Why is there a high rate of positive hair follicle mite tests in patients with facial dermatoses? The pathogenesis may be due to the widespread topical application of various doses of corticosteroids, which to varying degrees cause a decrease in local resistance of the skin, leading to Trichophyton rubrum infection. On the other hand, it may be related to the increase of domestic pets and cross-infection caused by human-animal contact. 4, prevention and treatment of human helminth mites It is generally believed that the harm caused by mites to humans is not as terrible as some businesses advertise. To prevent worm mite infection, attention should be paid to personal hygiene and environmental sanitation. Asymptomatic or less symptomatic infections do not require special treatment, while those with more pronounced symptoms can be treated with medication or physical methods. In particular, acne and rosacea need to be treated symptomatically, including oral metronidazole to kill the mites, oral vitamin to eliminate inflammation of hair follicles and sebaceous glands, and some need to use tetracycline antibacterial drugs and vitamin B6 to regulate sebaceous gland metabolism. The topical antihelminthic mites are often metronidazole or sulfur-based preparations, such as sulfur cream and compounded metronidazole cream. The herbal tincture of Pepto Bismol is also effective. Prevention is important, pay attention to facial cleanliness and hygiene, use sulfur soap, warm water to wash the face to remove facial oil, skin care products should be used to wrap oil creams. Banana, apple, cucumber mud mask has astringent effect, suitable for oily skin people. In addition to some conventional drugs, some useful attempts have been made, the experimental results show that: 75% alcohol and 3% Lysol insecticide effect is good, but the action time must be more than 15min; 0.1% Neosporin insecticide effect is not obvious, the role of 30min after the mites are still active; 2% chloramphenicol alcohol has a certain insecticide effect; 2% methomyl alcohol solution than simple 2% methomyl aqueous solution insecticide The effect was obvious; 1300 cases of human crepuscular mites were treated with compound chloramphenicol spiritus externally and methicillin (metronidazole) internally, and the total effective rate was 98%. Some experts will live crepuscular mites under the microscope for peppermint oil emulsion drop experiment, confirmed that the drug action after 3h all kill crepuscular mites; 50 patients with drug treatment for 1 month, the results of 30 cases of mild disease effective; in the peppermint oil emulsion with metronidazole, and oral metronidazole treatment is more effective. In conclusion, parasitism of crepuscular mites is widespread, with different clinical manifestations, some with severe symptoms and some with mild symptoms, and the specific causes are still not clear, and the preventive and therapeutic drugs need to be further developed and perfected.