Research Progress on the Cause of Sensitive Skin

According to incomplete statistics, about one-third of people at home and abroad have suffered from allergic diseases in their lives, and women with sensitive skin in various regions account for more than 50% of the normal population. Sensitive skin is caused by a variety of reasons for skin allergies. Generally, the initial symptoms of itching and scaling on thin and tender parts of the skin, such as the face, gradually develop into mild edema, blisters, pimples, desquamation, and infiltration of the ear, neck, and even the whole body Sexual moss and other changes have characteristics such as unknown etiology, high incidence, easy diagnosis and difficult to treat, and affect the physical and mental health of patients.

Clinically, patients with recurrent facial dermatitis, eczema, atopic dermatitis (AD), hormone-dependent dermatitis, acne, seborrheic dermatitis, urticaria and other allergic dermatitis are common.

In recent years, a series of questions about sensitive skin have gradually become a topic of concern between doctors and patients, and how to find the cause of sensitivity is of great significance for diagnosis and treatment.

1. Genetic inheritance of sensitive skin

Early clinical findings found that people with different constitutions are prone to allergic reactions, mainly due to the genetic influence of first-degree relatives. Caucasians are highly sensitive to alcohol, peanuts, and sunlight. Yellow people have a high response to trees, grass, and cockroaches. Skin acupuncture IgE levels changed little in blacks who tested positive. Other studies have found that black people have a higher probability of developing allergic diseases than white people. Allergies have little to do with family inheritance and related medical history. The above differences suggest that racial genetic factors have a certain effect on allergic reactions.

1.1 HLA-Ⅱ gene related

The involvement of human major histocompatibility complex (MHC) genes in controlling allergies has been proven as early as the late 20th century. Immunology believes that various antigens are mainly controlled by the MHC-Ⅱ gene into the body. After binding to the human leukocyte antigen (HLA) molecular peptide binding groove and antigen presenting cells (APC), they are combined with HLA-Ⅱ The molecule-forming complex is recognized on the surface of the APC by HLA-II class-restricted T cells, resulting in an imbalance of Th1 and Th2, Th2 secretes interleukin-4 (IL-4) and interleukin-13 (IL-13), and induces immunoglobulin E ( IgE). Studies have found that HLA-DR3 and HLA-DR7 genes in Han patients who are positive for house dust mite antigens increase the frequency of HLA-DR3 and HLA-DR7 genes, which in turn induces the onset of AD, while other HLA-DR sites have no specific correlation with AD. Another study found that the increased frequency of HLA-DR7 and DR4 genes induced sensitive reactions; the increased frequency of HLA-DQA1 * 0301 genes in the British induced the occurrence of allergies; a Japanese study found that HLA-DRB1 * 1302, DQB1 * 0406, DPB1 * The increase of 0301 gene frequency and the decrease of HLA-DR4, DR53, and DQB1 * 0406 gene frequencies are all related to specific responses.

The above research populations, methods and results are different, but it is clear that the skin sensitivity of the population may be affected by multiple gene loci and gene frequencies, and the specific response is related to the HLA-DR gene. The correlation between the diversity of HLA gene loci and the binding positions of peptide grooves of exogenous substances, and the correlation between the cortical expression and the degree of response to stimulate the body is unknown.

1.2 Gene region correlation

Online Human Mendelian Genetics (OMIM) recorded “11q13.5, 13q-12-q14, 5q131-q33, 3q21, 1q21, 17q25, and 20p gene linkage” as susceptible gene regions in AD. The susceptibility genes of the populations in different regions are different. The susceptibility gene region of the German AD population is 11q13.5, and the susceptibility loci of the Japanese AD population are located at 1q24 and 15q21. The current study found that the susceptibility loci of the Han people are 5q22.1 and 20q13. .33. With the deepening of research, candidate and newly discovered gene regions are also increasing. For example, a 2011 study based on the European population found that new susceptible gene regions were 11q13, 19q13.2, and 5q31.1, and Japan added new susceptible gene regions. Sense genes are 2q12, 3q13.2, 3q21.33, 7q22, 10q21.2, 20q13, 6p21.3, and 11p15.4, and 1q21.3 and 11q13.1 of the Han population are AD risk genes. With the increase of research, OMIM may enter more specific susceptible gene regions, and the related research around the susceptible gene regions of the Han population is worthy of further study.

2. Age and gender of sensitive skin

Allergic reactions at different ages have different characteristics, and infants and young children have a higher rate of food allergies. Clinical studies have confirmed that 84.6% of AD patients in the Han ethnic group develop disease within 2 years of age. Male infants and young children are more severe than females. Based on eczema And multiple statistical analysis studies of AD confirm this view.

Adolescents are prone to inhalation and contact allergies, while young and middle-aged women are prone to facial and skin problems. If surveys show that women account for 86.5% of steroid-dependent dermatitis, and 56.8% are young women aged 20-40. Older people have a weaker response to old allergens and a lower chance of new allergic reactions, and dry itching caused by reduced skin moisture may cause new skin problems.

2.1 Infants and food allergies

More than 60% of children with eczema are related to food allergies. Infants and young children are allergic to milk and eggs, which mainly occur within 1 year of age and are related to intestinal flora disorders. Infants and young children are allergic to intestinal colonization of less bifidobacteria and lactobacillus, while more enterobacter and staphylococcus, a lower proportion of anaerobic bacteria, a higher proportion of aerobic bacteria. Due to the inability of the intestinal flora to form a stable biological barrier, the immune system is not yet mature, and the immune response is reduced, resulting in greater intestinal permeability, and harmful substances (such as passing bacteria, food antigens, inflammatory cytokines, etc.) invade the intestinal blood circulation System, induce food allergies and a series of skin inflammation reactions. The skin inflammation response rate is still relatively high in adults, which may be due to the continuous stimulation of intestinal flora affecting the development and maturity of intestinal lymphoid tissues in children. The current research points to the influencing factors of intestinal flora change to allergic diseases, then the prospective research on the qualitative and quantitative relationship between food and intestinal flora (type, quantity and characteristics) will become a new problem, which will affect children after adulthood. The impact relationship has yet to be confirmed.

2.2 Adolescents with inhalation allergies

With growth and development, changes in living habits and the environment, they are gradually immune to allergic foods in early childhood, and adolescents are allergic to inhaled substances. The results of research on inhaled allergens at home and abroad are relatively consistent, mainly for house dust. , Mold mites, cockroaches, pollen, etc. Inhalant allergy may be related to the patient’s epidermal high-affinity IgE receptor, which specifically binds sensitive substances and stimulates the respiratory mucosa to produce an allergic reaction that can further induce skin inflammation. In addition, a study based on the Korean population found that increases in total IgE in children who are allergic to cockroaches are associated with high serum vitamin D levels. The consistency of inhaled allergens at home and abroad indicates that there are similarities in the atmospheric composition and inhaled substances in each region, but it does not mean that other undetected inhaled ingredients do not cause allergic reactions, and that the sexual relationship between inhaled substances and allergic reactions The relationship between occurrence and serum factors is unclear.

2.3 Facial dermatitis in young and middle-aged women

Clinical statistics: The disease is mainly caused by young and middle-aged women. It may be caused by women’s excessive attention to the skin at this stage, after improper maintenance or treatment (mainly using cosmetics or drugs containing allergic substances or hormones) Allergic substances induce allergic reactions, hormones interfere with cell DNA synthesis and mitosis, and inhibit proliferation and differentiation of skin keratinocytes and other cells. Eventually, the skin caused by the loss of percutaneous water (TEWL), thinning of the horny layer, abnormal skin structure, and enhanced stimulus signals and immune response after skin dysfunction. The most commonly affected areas are the suborbital, palate, and forehead, which are mainly characterized by dryness, scaling, redness, itching, and burning pain.

2.4 Elderly women with pruritus

With the increase of age, the skin experience is gradually enriched, the sensory nerve function of the skin is gradually reduced, the nerve distribution is gradually reduced, and the tolerance is gradually increased. New allergens may no longer be the main annoyance of the elderly. However, with aging, the sebaceous glands shrink, TEWL decreases, and the ability of the skin to synthesize hyaluronic acid decreases, which leads to dry skin and reduced desquamative pruritus caused by oil secretion, which becomes a new problem. Pruritus in the elderly is related to IgE-mediated allergies, while Chen Zairong et al. Believe that IgG4 is a specific antibody involved in skin pruritus in the elderly, which mainly mediates food and inhalant allergic reactions. It can be seen that allergic reactions can be mediated by multiple specific antibodies, which also provides new research ideas for allergen detection.

3. External stimulus of sensitive skin

3.1 Allergen

Allergens can be divided into contact, inhalation, ingestion and injectability according to the invasive route. The testing methods and populations studied are different, and the results are complex and different. According to incomplete statistics and clinical observations, the inhaled matter is mainly dust mite allergens, the ingested matter is mainly milk and shrimp, the contacted matter is mainly pollen, the facial contacted matter is mainly cosmetics, and skin allergies other than the face are allergic More common ointments. Β-lactam antibiotics are common for injectable drug allergies, and penicillin allergy and the HLA-DR9 gene confirm this view. Allergen-induced allergic reactions and the correlation between the diversity of skin lesions and HLA genes may become a new research hotspot. The currently used detection methods include skin prick tests, intradermal tests, patch tests, and serum allergens. Detection method, gene chip technology, biological resonance allergen detection method. Among them, the bioresonance allergen detection method has been questioned because it has no evidence-based medical support.

3.2 Humid environment

Sensitive skin is affected by multiple factors such as sunlight, temperature, season, and environmental pollution. Many studies believe that microbial invasion is the main cause of skin sensitivity in people with dermatitis and eczema. Studies have found that the overall detection rate of skin bacteria in patients with dermatitis and eczema is 67.78%, and the detection rates of S. aureus and Malassezia are 31.11% and 47.78%, respectively. Microbial reproduction can damage the skin barrier, S. aureus penetrates the AD skin barrier and induces changes in IgE levels. Malassezia furfur mediates IgE elevation in AD patients and can trigger type I allergies.

In fact, the human body is parasitic with a variety of microorganisms. Only when the humidity is high and the temperature is appropriate, the skin can quickly become a high-quality medium for certain microorganisms. The continuous growth invades the skin’s surface layer, and eventually induces skin allergies. The study of how the difference in humidity and temperature in the humid environment causes skin disease is worthy of research attention.

4. Deficiencies and Outlook of sensitive skin

There are many reasons for inducing skin sensitivity, and clinical diagnosis and treatment is also the key to affecting prognosis. As far as the doctor is concerned, solid diagnosis and treatment technology is important, guiding patients to investigate the cause, rational use of cosmetics, and nursing psychology have a very important role; for patients, do a good job of long-term confidence in the care, to eliminate the use of Sanwu products, reasonable Choosing maintenance methods and correcting habits such as smoking, picky eaters, constipation, and irregular schedules are all conducive to improving skin problems. At present, the etiology and pathogenesis of skin sensitive systems are not clear, and in-depth research on the application of medical cosmetics is lacking. How to choose appropriate drugs and skin care solutions based on the skin condition of patients has become a common problem faced by doctors and patients.

5. Solution of sensitive skin

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