0:07Hello, I'm Dr. Peter Lio.
0:08I'm a clinical assistant professor of Dermatology and Pediatrics at Northwestern University Feinberg School of Medicine in Chicago, Illinois.
0:16And today I'd like to ask the question about the root cause of eczema?
0:21What is it? What does it mean? How can we address it?
0:25And I would say that it is a key question, but unfortunately, it is not as easy as it looks.
0:31The root cause of atopic dermatitis seems to be somewhat elusive because it's not one thing.
0:39We think that it is multifactorial and probably different for different people.
0:43So some patients really do seem to have a primary genetic condition where they are not making enough filaggrin protein.
0:53For those patients, I feel pretty confident, pretty comfortable that we can say, the reason you have this disease is because your skin barrier is supposed to be strong and tight, but it's leaky.
1:02So water leaks out very easily, like trying to hold water in a colander.
1:09And allergens, irritants, pathogens like bacteria and viruses, all these things, pollutants can get into the skin driving your immune system absolutely crazy, which then drives the inflammation and itch, which it turns out then in turn further damages the skin barrier and drives more inflammation.
2:06Now, in the middle of all this crossfire, of course, is the microbiome.
2:09The microbiome is also playing a role in this, and when the skin barrier is damaged, the microbiome becomes very abnormal.
2:14In addition to that, the nerve endings in the skin actually change.
2:19So those nerve endings become different morphologically, and they send the sensation of itch more easily.
2:24And then finally, we even have a bigger piece, the behavioral aspect, the mind-body connection in this condition actually changes too.
2:31People over time, they find that they have behavioral cycles of poor sleep, of stress and anxiety,
2:39and even just raw behavioral things. I have some patients when they're just feeling anxious about something, or if they're getting upset, they just start scratching at their skin, and that can trigger a whole flare up.
3:25So in some patients, we could say the root, root, root cause, if you go all the way down, is a genetic issue with filaggrin encoded by a gene called the FLG gene.
3:36And that explains some of it.
3:38But you can see even when the genetics is the first thing, right, there are other pieces that are really playing a role.
3:44So for a given day, the root cause, if you will, what triggered the flare up, could be very, very different in the context of these things.
3:52It could be hot weather with sweating, it could be really cold, dry weather, it could be putting a fabric on that drove the skin crazy.
4:00Sometimes it might even be something somebody ate.
4:02But usually we're not that lucky that it's one thing.
4:04Sometimes you'll hear people say, well, I think it's all in the gut.
4:07And I think that's partially true.
4:09We think the gut is definitely involved, because if you trace your skin around your lips, that becomes your gut.
4:15It's all part of the epithelium.
4:17So there's no doubt the gut is involved, but I don't think it's all in the gut or only in the gut, because we know the skin is abnormal.
4:23We can show that the skin barrier is leaky and damaged.
4:26And we understand that again, especially for patients like the ones we've described, their gut barrier is probably messed up too and impaired too,
4:34but that didn't necessarily come first and is definitely not the only piece.
4:40So it really makes it sense why it's so difficult to easily answer this question,
4:46but what we can think about is how can we get all of these aspects better and break all these bad cycles?
4:54And what we find is that if we can do that, it sort of doesn't matter what the root cause was.
5:00Because like a forest fire, yes, it could be helpful to find the kid who threw the matches, started the fire, the arst, but at some point it doesn't matter anymore, that patient that person may be long gone.
5:12We have to put out the forest fire and get things back in order.
5:18And even if we never find one trigger or multiple triggers that are the key responsible things.
5:24If we can find things that we know are harmful, and we can help the skin heal, get the barrier stronger, get the microbiome more robust, I think that for many patients, we can get them in a place where it didn't really matter what the original inciting factor was,
5:39but we have them in a good place now.
5:44I hope that's helpful and I look forward to seeing you in the future.
5:47Thank you.
