| Background and ObjectiveAcne is a dermatosis marked by chronic inflammation of the hair follicle and sebaceous glands. Acne has a lot of pathogenic factors and various clinical manifestations, which is mainly characterized by comedo, papules, pustules, nodules, cysts and scars. Acne attacks frequently and repeatedly during adolescence, so it influences severely the patients in the aspect of skin,mind,and so on. In the recent years, studies on the pathogenesis and treatments of acne have been paying more attention by clinicians. Nowadays, there are multifarious methods and medicines used in acne'treatments, however, the healing effect is not very satisfactory, especially the adverse side effects. One of the difficult problems, in our current medicinal period, is the high recurrence rate of acne, which is still unresolved.The high intensive narrow band blue light (407nm~420nm) is a new physical therapy, which, recently, is gradually developed in clinical circles.The therapeutic mechanism of blue light toward acne is that a large amount of porphyrins produced by P.acnes will be activated when they are exposed to the visible light (320nm and 415nm),then a series of photochemical reactions develop until the P.acnes are killed.The main pathogenic microorganism of acne is P.acne, a anaerobic bacteria which make the acne attack frequently and repeatedly as well as bring injuries to skin. P.acnes synthesizes and stores a large amount of porphyrins, especially the Coproporphyrinâ…¢in the cell membrane. Coproporphyrinâ…¢is similar with the chromophore, which is sensitive with the visible light of 320nm and 415nm.When the Coproporphyrinâ…¢is exposed to the light of these wave lengths, it'll be triggered the photochemical reactions, then result in the formation of singlet oxygen, which will destroy the P.acnes.It is commonly known that the wave length of ultraviolet A is 320nm~400nm, and the one of ultraviolet B is 275nm~320nm.The sensitive visible light of Porphyrin IX, 320nm light is the critical wave length of UVA and UVB, which can cure the acne in the theory. Yet, the treatment of UV has a lot of side effects such as the tanning, the flare and the desquamation of skin as well as the photocomedogenicity phenomenon.In the initial state of physical therapy, clinicians used the UV to cure the acne, but it was discarded in the end because of the serious side effects. However, the high intensive narrow band blue light releases the visible light of 407nm~420nm, which has two advantages. One is that the blue light has ability to stimulate the PpIX with the suitable light of 415nm; the other aspect is that the blue light belongs to the narrow-spectrum, which decreases the harm of invalid light. So, the blue light is considered of the most effective visible light to activate the PpIX, in other words, the blue light is the most effective visible light to kill P.acnes. The Selective Photothermolysis will bring us a bright prospect in the aspect of acne's therapy.There are many pathogenic factors causing acne, such as the excessive sebum production, ductal cornifcation, and polymicrobic colonization in the pilosebaceous duct, which do induce acne. The excessive sebum production and the recurrent attacks of skin rash cause the decrease of skin elasticity, the patulous follicular orifice, and the disproportion of the skin water content, which not only destroy the physiognomy, but also increase the chance infected acne.Therefore, it is contributed to observe the effect that blue light influences some pathogenic factor of acne and assess the treatment effectiveness preferably, if we pay more attention to the change of the skin property of patients. Malassezia furfur is an opportunistic organism, and a kind of saccharomycete, which is used to live in the high fat environment. Although M.furfur is not the main pathogen of acne among the numerous ones, it is reported that there are many M.furfur in the inflamed and hormonal acne. Especially, when the acnes attack frequently, the treatment effectiveness of antimicrobial drug to P.ance is not effective. Therefore, it is very necessary to pay more attention to the effect that M.furfurs induce acne and look for an effective treatment.In order to observe the curative effect of the high intensive narrow band blue light (407nm~420nm) towards acne, we'll prepare to perform many experiments from three aspects. Firstly, we'll observe the effects, the recurrence rate and the side effects on the therapy of blue light towards acne. Secondly, we'll execute the test of skin property and SER, so as to assess the change of sebum after the therapy. Thirdly, we'll research the bactericidal effect of blue light on acne, in order to evaluate the treatment effectiveness of the high intensive narrow band blue light (407nm~420nm) on acne preferably.Methods1. The patients were topically irradiated by the high intense narrow band blue light (407nm~420 nm) twice weekly and the treatment lasts 15-18 minutes every time, each period of treatment lasts for 4 weeks. The electron microscope was used to observe the changes of acne, as well as the epidermis and dermis around the target acne.2. To test the property of skin before and after the course of eight treatments in order to observe the curative effect and the changes of Sebum, water content,elasticity,and follicular orifices. The improved methods of"Looking bill"and"Cunliffe"were applied to test the sebum excretion rate(SER).3. The M.furfur suspending liquid was irradiated by the blue light in order to observe the number and the colonial morphology.Results1. There are 95(79.2%)cases were healed completely, 12(10% )cases had marked effect, 8(6.6%)cases had effect, 5(4.2%) cases without effects and the cure rate was 89.2% after 120 patients cured by blue light. In the follow-up period(six months), there are 74 cases(92.5%)in 80 patients have no recurrence. The target acne has disappeared remarkably after the cures, and the injuries of epidermis and dermis lessened as well.2. After the cures of blue light, the SER of patients lessened markedly, the elasticity of skin increased, and follicular orifices shrank, however, the water content didn't change.3. After the M.furfur was irradiated by eight cures of the blue light, the number and the diameter of bacterial colony decreased gradually with the irradiation of blue light.Conclusions1. The high intensive narrow band blue light(407nm~420nm) has proven to be an effective method to acne, which can remarkably reduce the recurrence of acne, restore the injuries of epidermis and dermis, and have less side effects.2. Blue light can lessen the SER, increase the elasticity, shrink the follicular orifices, and doesn't change the water content of skin, so as to it has good curative effect to improve the skin property, and to prevent the recurrence of acne. 3. Blue light is an effective antibacterial method to M.furfur, which is reported for the first time in the whole world.
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