Ebook Acne causes and practical management: Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Acne causes and practical management: Part 2
Ebook Acne causes and practical management: Part 2
CHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2gn materials. Remember that foreign Is defined as anything that is not supposed to be in the dermis, and the dermis Is that part of the skin that is below (on the dermal side of) the basement membrane. And remember that the basement membrane runs horizontally under the epidermis but dives deep and w Ebook Acne causes and practical management: Part 2raps around the epidermal appendages, all of them, from sweat glands to hair bulbs. It Is thin In some areas, thicker in others. Il follows the contouEbook Acne causes and practical management: Part 2
rs of the folUciilopilosebaceous unit (FPSU) like a vinyl glove on your lingers. It provides support to the appendages. It anchors the epidermis to thCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2nd the appendages. (See Figure 2.7.)A recently described chemical messenger system, hypoxia-inducible factor I (HIF-1). may l»e responsible for the two processes that arc active at this point in the process of acne development. HIF-1 appears to be able to induce 'hyperproliferation and incomplete di Ebook Acne causes and practical management: Part 2fferentiation of epidermal keratinocytes' |l|. It Is also *a major regulator of cellular adaptation to low oxygen stress* and 'plays an important roleEbook Acne causes and practical management: Part 2
in cytokine production by keratinocytcs and in neutrophil recruitment to the skin* |2|. Thus, It may stimulate the overgrowth to bursting and recruitCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2OÍ the FPSU becomes "visible* to the body's immune systems. This can happen if the immunecells find their way through a split in the basement membrane into the follicular duel, or if the materials inside the duct find their way out through a leak. Either way, the immune systems recognize the foreign Ebook Acne causes and practical management: Part 2 material. and this Is the first trigger to inflammation. If and when the immune reactions proceed, the duct leaks even more and often ruptures, and gEbook Acne causes and practical management: Part 2
reater volumes of materials in the duct find their way out into the dermis. There they trigger the numerous inflammatory processes of the Innate and aCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2e inflammation. Then we can plan to eliminate each and everyone of them.6.1 Propionibacterium acnes (P. acnes)Bacillus acnes, the 'acne bacillus,* was first described by Gilchrist in 1900. Il was renamed Corynebacterium acnes In 1909 and later Propionibaaerium acnes (P. acnes). There are 22 members Ebook Acne causes and practical management: Part 2of the Propionibacterium family, but p. acnes (which comprises several strains) appears to be the only important one in acne. As such, it has been theEbook Acne causes and practical management: Part 2
target for elimination by dermatologists for decades. But there is a problem, simply overwhelming the population of p. acnes with antibiotics doesn'tCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2Praaieal Management, First Edition. F. William Danby.©2015 John Wiley b Sons, Ltd. Published 2015 by John Wiley b Sons. Ltd.9394 Acne: Causes and Practical Management6.1.1Normal role of p. acnesWhile It has been generally accepted that p actus is a normal organism on everybody’s skin (a commensal), Ebook Acne causes and practical management: Part 2that is not the whole story. Recently, with a simple but sophisticated technique. Bek-Thomsen showed that p. dates seems to have exclusive rights OÍ oEbook Acne causes and practical management: Part 2
ccupancy to the FPSU. His work shows that no other organism can make that claim [3J. Furthermore, It was suggested that this relatively harmless organCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2ve role really work?Imagine that p. nates Is sitting quietly In a follicle. It is a facultative anaerobe. That means It can survive and multiply In a very low-oxygen (or no-oxygen) environment. Normally, the follicle is well oxygenated so p dates' motor is simply ‘idling in neutral.* If there is a m Ebook Acne causes and practical management: Part 2inor injury to the duct, like a scratch or a nib, a little bit of p. dates antigen may leak out of the duct. Or, much less likely, perhaps a wanderingEbook Acne causes and practical management: Part 2
dendritic cell bearing toll-like receptor 2 (TLR2) may gain access to the ductal lumen. If such contact is made between p aates and the innate immuneCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2inflammation* Is really designed to return the physical structure of the duct back to normal. Ute inflammatory system we work so hard to suppress is not all ‘destruction”—its reparative function is usually ignored, and many of the medications we use will actually compromise this function. Topical st Ebook Acne causes and practical management: Part 2eroids, for instance, cause thinning of the skin in hand eczema, a thinning that takes months of steroid avoidance to repair.Barring serious abnormaliEbook Acne causes and practical management: Part 2
ties (like the overstuffed duct with weak walls in acne inversa), the repair is quickly completed and everything goes back to normal. p. dates' role aCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2e.6.1.2Pathogenic role of p. acnesWe are much more familiar with p. denes' role as a pathogen, a bad actor that needs to be eliminated In order to cure the disease. Over the past 60 years, we have brought to bear tetracycline, erythromycin, doxycycline, minocycline, lymccycline. azithromycin, sulfa Ebook Acne causes and practical management: Part 2drugs with and without trimethoprim, clindamycin.clarithromycin, ampicillin, amoxicillin, ciprofloxacin, and even rifampicin. Despite this aggressiveEbook Acne causes and practical management: Part 2
attack, we still see the term antibiotic-resistant date, and that term usually addresses only acne vulgaris. If you add acne rosacea, then metronidazoCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2I/HS), and we sec that escalation to the ‘nuclear option* Includes long-term systemic rifampicin, moxifloxlcin, and metronidazole (5|. It is hard to believe that any bacterial infection could survive that onslaught, and yet only 16 of 28 patients with HS/AI achieved complete remission with up to 12 Ebook Acne causes and practical management: Part 2months of this aggressive triple-antibiotic therapy. We have not yet learned what will occur when the medications are stopped In those temporarily forEbook Acne causes and practical management: Part 2
tunate 16 successfully treated patients. But we can guess.What happens to change p. dates from a mild-mannered commensal to a 'pathogen' able to destrCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2tes, and one that has been roundly ignored despite posted warnings.First, p. dates shifts out of neutral and really gets to work only in an anaerobic (no-oxygen) or a microaero-philic (low-oxygen) environment. So, how docs one achieve such an anoxic environment in a healthy teenage face, full of lif Ebook Acne causes and practical management: Part 2e and the vigor of youth, well vascularized, and supplied with adequate nutrients and all the metabolic systems needed to sustain and repair all normaEbook Acne causes and practical management: Part 2
l processes? The answer is possibly, but not proven, that there is simply too much of a good thing available. As described In detail In Section 2.9, ICHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 21. overstimulate the follicular ductal keratinocytes. A traffic jam occurs in the follicle: pressure within the confines of the follicular duct compromises the availability of nutrients, especially oxygen. Hie lack of nutrients diffusing into the area Interferes with normal metabolic processes withi Ebook Acne causes and practical management: Part 2n the keratinocytes. The concurrent anoxia provides a wonderful place for p. dates to flourish. Nourished anaerobically by the fatty acids of the sebuEbook Acne causes and practical management: Part 2
m, p. dates multiplies mightily, to the point that the colonies are large enough to be easily visible in microscopic sections. When the overstressed fCHAPTER 6Follicular flora, fauna, and fuzzThe inflammatory reaction that causes the trouble in all the acnes is directed at a limited number OÍ foreig Ebook Acne causes and practical management: Part 2, becoming a very potent stimulus of the innate immune system. That is what lights the fire In acne vulgaris.Second, p ames has the genomic capacity to support a large number of functions. These enzymatic abilities are not much in evidence when the organism is 'idling* quietly in the duct, but under Ebook Acne causes and practical management: Part 2 the conditions of anoxia that occur in the compressed confines of the crowded and distended duct, the organism Is capable of springing to life at fulEbook Acne causes and practical management: Part 2
l anaerobic throttle, and the broad panel of metabolic options that the genotype can support apparently become selectively deployed. This shows up asGọi ngay
Chat zalo
Facebook