Acne Pathogenesis
Acne pathogenesis. The professor of anatomy will tell you it's an anatomical problem, and the problem we talked about was blocking of the follicular canal, and we'll review that. Yes, there is sebaceous gland sebum changes, everybody gets those changes, not everybody gets real bad acne. P. Acnes: P. acnes provide lipase that can take the triglyceride and release its free fatty acids irritating, and probably more important, it provokes polymorphic neutrophils at a vessel and into the pilosebaceous unit, turning it into a real inflammatory papule or pustule, because it has a chemotactic that draws it out. And yes, there are certainly endocrine changes at puberty, everybody has them, not everybody has amazing acne.
Sebaceous Follicle
So, let's do this quickly. Here we have a happy sebaceous follicle, busy oil glands, a nice thin, wispy lining in red, a few bacteria suppressed by the presence of oxygen in blue.
Microcomedo, Closed and Open
Comedones
The beginning of problems is when the lining gets thicker here in red, and the oil is not getting out quite as well, and that could lead to a closed comedone or a whitehead, or if the pressure of oil pushes this block to the surface, an open comedone or a blackhead. This nice thin lining has been changed. Here one or two cells thick, without lipids, and in the comedone stage it's much thicker, oily, retentive, it's blocking up the works, you've got to address it, you have your comedone.
Well, while you're blocking up the works, the oxygen no longer is present, and the bacteria start to grow, causing inflammation, and sending out the chemotactic. Polys come in and the comedonal system will be papular and pustular. There are hydrolytic enzymes from the bacteria themselves, pressure, and material will start leaving, like a water balloon that broke, will leave the pilosebaceous area and move into the normal dermis. The body won't tolerate that very long, because it's oil, it's bacteria, macrophages will come in and glop up this material, but in doing also can also glop up normal collagen, and then you have acne scarring.
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