The Role of Skin Barrier Repair in the Treatment of Acne

Skin is the largest organ of human body, with the function of barrier, absorption, secretion, excretion, metabolism, immunity, body temperature regulation and sensation. The skin barrier function is the most basic and the most important link, which takes part in the invasion of antigens, microorganisms and sunlight, prevents the loss of nutrients and water in the body and maintains normal physiological functions. The broad definition of skin barrier function includes not only physical barrier, but also pigment barrier, nerve barrier, immune barrier and many other aspects related to skin function; In the narrow sense, the barrier function usually refers to the physical or mechanical barrier structure of the epidermis, especially the cuticle. (the barrier function mentioned below refers to the barrier function in the narrow sense.) The cuticle is the most important component of skin barrier. The damage of skin barrier is varied, which can be manifested as the imbalance of water and lipids, as well as the destruction of lipid bilayer and cuticle structure. Therefore, the skin barrier function can be judged by determining the skin’s various physiological functions such as water content of the cuticle, lipid content, pigment, and transdermal water loss. Damage to the skin barrier can induce the production of various skin diseases, such as ichthyosis, pruritus, inflammatory skin diseases. The role of skin barrier repair in the treatment of acne is summarized below.

1. Acne and skin barrier function

Acne is a chronic recurrent inflammatory skin disease occurring in the hair follicle sebaceous glands. In China, zou Xi et al. measured the cuticle moisture content, lipid content and TWEL value of 80 acne patients and found that the skin lipid content and TWEL value of acne were higher than the healthy control, and the cuticle moisture content was lower than the healthy control, suggesting that the skin barrier of acne was damaged. In contrast, Wu Yanyu et al. studied 75 cases of mild and moderate acne, and found that the skin water loss rate in the skin rashes was significantly higher than that in the normal parts, and the saturation value of sebum and the secretion rate of sebum were significantly lower than that in the normal parts, and the skin barrier function damage was positively correlated with the severity of acne skin lesions. Yamamoto et al. compared the skin physiological functions of 36 acne patients and 29 healthy controls, and found that all of them had increased skin water loss and sebum secretion, accompanied by decreased water content in cuticle. It is worth noting that the abnormal sebum secretion of acne patients not only presents the increase in quantity, but also has the problem of abnormal sebum composition. Meyer found that the neuramide secretion in acne patients was insufficient, and the neuramide had the effect of inhibiting the inflammatory response, so the deficiency of neuramide further aggravated the inflammatory response.At the same time, it was also found that the barrier function of acne patients was impaired in different seasons. In summer, sebum secretion was mainly increased, while in winter, percutaneous water loss was more significant.

Both domestic and foreign observations have found that the skin barrier of acne patients has been damaged to varying degrees, which is mainly manifested by the increase of epidermal water loss, excessive lipid secretion, abnormal lipid composition and reduced water content in the cuticle.This provides the basis for clinical treatment.

2. Factors affecting the acne skin barrier

2.1 Effects of common drugs on the skin barrier

2.1.1 Vitamin A acid

Oral isotretinoic acid is the most effective drug to treat acne, but it can affect the epidermal barrier in many ways. First of all, oral administration of iso-retinoic acid can reduce the bridge granules, thus resulting in less brittle intercellular connections and increased epidermal reversion. Studies have shown that oral isovitamin A can increase TEWL and there is A dose-dependent relationship.The effect of isovitamin A on skin sebum was more significant. A decrease in the level of skin lipids is usually observed after 1 month of treatment and continues with the continuation of treatment.After 4 to 5 months of treatment, the sebum level gradually recovered to the pre-treatment level. The response of external use of allo-a acid to skin is A treatment related reaction. Similar to oral administration of allo-a acid, external use of retinacic acid can also cause burning, stinging, pruritus, erythema, dryness and other reactions, and the moisture content and TEWL increase.

2.1.2 Benzoyl peroxide

Benzoyl peroxide is one of the most important topical drugs for acne. It has anti-propionic acne-bacillus, anti-inflammation and anti-keratinization effects, and has therapeutic effects on inflammatory skin rashes and acne. However, it is found in clinical practice that some patients will develop intolerance, such as tingling, erythema, etc.Studies have shown that benzoyl peroxide can induce lipid peroxidation in the cuticle, which changes the lipid composition of normal cuticle and leads to damage of epidermal barrier. In addition, benzoyl peroxide can also oxidize keratin, such as keratin 1 and keratin 10, so that the cuticle thickness of the epidermis is reduced and the sensitivity of the skin is increased.Repeated use of benzoyl peroxide significantly increased TEWL.

2.1.3 Antibiotics

Oral minocycline and doxycycline had little effect on skin barrier function, while external antimicrobial agents mainly affected microbial flora.Topical antimicrobial agents can induce colonization of staphylococcus epidermidis.

2.2 External cleaning agent and skin barrier

There are a wide variety of cleaners, mainly divided into four types, namely soap, synthetic detergent, antibacterial soap, soap – free detergent.

2.2.1 soap

Soaps are usually long chain fatty acid and alkali saponification, and their pH value is often greater than 7.The advantage of soap is strong cleaning ability, can remove the dirt and grease on the skin surface efficiently.It is also because of its strong cleaning power, the soap often can remove the normal lipids and proteins of the skin, and increase the absorption of topical drugs through the epidermis, causing a stimulus response.In addition, the soap can also increase the pH value of the skin, increase water loss through the epidermis, cause dry skin chip removal, and further induce the occurrence of inflammation.Therefore, soaps are not suitable for cleaning the face.Antibacterial soap such as safeguard is added on the basis of soap.Antibacterial soap is not suitable for facial cleaning of patients with acne, because antibacterial soap is mainly used to clean bacteria on the skin surface, mainly the bacteria that needs oxygen gram-positive staining, while acinetobacter propionibacterium is mainly located in hair follicles and sebaceous glands, and the general antibacterial agent cannot penetrate to the corresponding parts, and its effect on anaerobic bacteria is not good.

2.2.1 Detergent

Synthetic cleaners are made by adding other ingredients to traditional soaps. Compared with traditional soaps, the pH of synthetic cleaners is usually 5.5 ~ 7.0, close to the pH of normal skin.In addition to effective cleaning, synthetic cleaners remove less normal protein and lipids from the skin, so they feel less tense and dry after use.Soap – free cleaners are the most gentle on the market.http://www.iplbeauty.cn/ Normally this kind of cleaner is neutral to weak acidity, do not contain the irritant such as agent, pigment, essence, salicylic acid, after using, can form a thin layer to protect wet film on skin surface.Previous studies have shown that soap – free detergents are beneficial to patients with sensitive skin such as rosacea and atopic dermatitis.Current applications in acne are also available.

Draelos et al. evaluated the effect of Cetaphil cleanser on mild acne.The researchers studied 30 patients aged between 18 and 50 with stable mild acne and asked them to use cleansers twice a day without any medication.In terms of skin barrier, TEWL was slightly increased after 2 weeks, but the difference was not statistically significant, while the water content in the cuticle decreased significantly.The cleanser has no effect on lipid secretion.In terms of skin lesions, both the number of blackheads and the severity of acne were significantly reduced after two weeks of use.No signs of irritation or intolerance were found in the study.In another study, Subramanyan compared the efficacy and side effects of two detergents combined with benzoyl peroxide gel or adalparin gel.The results showed that compared with the use of soap, the patients with mild detergent had less reaction such as erythema, desquamation, burning sensation, and desquamation. Meanwhile, in terms of the removal of skin lesions, the severity score of acne of the patients with mild detergent also decreased significantly.Therefore, in the treatment of acne, synthetic detergent or soap free detergent can be the first choice.

3. A barrier repair strategy for acne skin

3.1 Facial cleanness

The untreated acne itself has the damage of epidermal barrier function, while the acne medicine and inappropriate living habits will further aggravate the barrier damage.Therefore, in the treatment of acne, skin care is particularly important.Facial cleansing is the first step in skin care, so choosing the right cleanser is the first step in barrier repair.Ideal cleaners should meet the following requirements:Yoga causes no irritation to the skin and does not cause dehydration.Rays alleviate or reverse skin barrier damage caused by other acne treatments;While maintaining normal skin pH level;Inflammation does not induce acne or inflammatory skin rash;Phenotype can reduce propionic acinetobacter reproduction and its mediated inflammatory response.As mentioned above, gentle facial cleansers have no effect on the skin barrier and can relieve adverse reactions caused by acne medications, so they are recommended for every patient.

3.2 Application of emollients

Emollients play an important role in the adjuvant treatment of acne.Emollients have three main characteristics, that is, locking water, moisturizing and softening.Water lock is mainly used to prevent water loss by forming a waterproof membrane on the skin surface, thus reducing TEWL, which is also an important application of skin moisturizer.The active ingredients of this component are dimethylsilicone oil, glycerin, mineral oil, etc.And protect wet basically is to increase the hydration action of the skin, make the water content of cutin layer increases, common active material includes hyaluronic acid, lactate salt, urea, sorbitol, glycerin.Softening is what makes skin smooth, and there are many of these substances, commonly known as dimethylsilicone oil.Emollients are an important means of maintaining and repairing the skin barrier.In the study of 29 adult female patients with acne by Isoda et al, it was found that the severity of acne was reduced and the dry skin condition was significantly improved after 4 weeks of use of the skin lotion/detergent combination.Cestone et al. studied the effect of a new skin lotion on acne.The subjects were 40 patients with mild acne, with 10 to 25 acne on each side.The trial was randomized, double-blind, placebo-controlled, once a day for eight weeks.After 8 weeks, the acne in the experimental group decreased compared to the baseline, while the TEWL value in the experimental group decreased by 7% compared to the baseline, and the sebum secretion decreased significantly. No adverse reactions were observed in the experiment.Another study showed the role of barrier repair products.The cohort study included 643 patients with acne, and 85.2% of patients were required to use barrier repair products, of which 36.1% had good compliance.Compared with the non-compliant patients, the patients using barrier repair products had better clinical improvement, and the compliance to the drug treatment such as retinoic acid was also higher.It can be inferred from this that barrier repair products, on the one hand, can alleviate adverse reactions of drug treatment and improve compliance, so as to obtain clinical efficacy, while barrier repair products themselves also have the effect of improving efficacy.So how do you choose a moisturizer?

Chularojanamontri et al. reviewed the main ingredients of 54 emollients and found that dimethylsiloxane and glycerin were the most commonly used because they reduced TEWL.Hyaluronic acid and pyrrolidone are also commonly used.Guo jianmei et al. evaluated the effect of collagen dressing on the facial barrier function of patients with mild acne by comparing the left and right face.The results showed that the amount of water in the cutin layer of the skin was significantly increased.Transdermal moisture loss was significantly reduced, and erythema, roughness and desquamation were lower in the treated side than in the control side.The number of inflammatory papules decreased and erythema index decreased.Collagen dressing alone can promote the repair of facial barrier function in patients with mild acne, and the recovery of skin barrier can help the recovery of acne skin rash.Ceramide is the main component of human cuticle lipid and an important factor for maintaining normal skin barrier function.Many kinds of ceramides have been found to be involved in the proliferation, differentiation and apoptosis of keratinocytes.Studies have found that acne vulgaris is often accompanied by a deficiency of ceramide, which can increase the tolerance of treatment and thereby improve clinical efficacy.Chunck et al. systematically reviewed the benefits of emollients in the treatment of acne.A total of 58 studies were included in the analysis, including 18 studies, 26 RCT studies, 5 cohort studies, 6 basic experimental studies, and 3 in vitro experiments.The literature review found that the treatment of acne was mainly related to the use of retinoic acid, mostly the drying and erythema caused by retinoic acid.Emollients, especially emollients containing ceramides, can significantly improve discomfort such as dryness and tingling, increase the compliance during the treatment process and improve clinical efficacy.Therefore, choosing the right moisturizer can improve the prognosis of acne.Ideal emollients should not induce acne, be hypoallergenic, and be unstimulating, matching existing treatment regimens.

3.3 Else

In addition to the above strategies, epidermal growth factor can also promote the repair of skin barrier.Kim et al. treated 20 patients with mild acne with recombinant human epidermal growth factor cream.The trial was conducted for six weeks using a half face placebo control.The results showed that after 6 weeks of treatment, the number of inflammatory skin lesions treated with growth factor decreased by 33.5 percent, while the number of non-inflammatory skin lesions decreased by 25.4 percent.In terms of skin barrier, the water content in the treatment side increased, while sebum secretion was significantly reduced, and TEWL value also decreased.

4. Epilogue

Acne is a common, multiple, and capacitive disease, and the skin barrier is damaged throughout the development and treatment of acne.Choosing appropriate adjuvants can improve the skin barrier function and make acne get better clinical efficacy.