Chemical Exposures, Pollen Flares & the Microbiome in Atopic Dermatitis

Learn how household chemicals, airborne pollutants, and seasonal pollen surges drive atopic dermatitis flares. Dr Peter Lio examines environmental triggers and microbiome disruption in AD for allergists and immunologists.

Peter Lio, MD is a Clinical Assistant Professor of Dermatology & Pediatrics at Northwestern University Feinberg School of Medicine.

Transcript

Hi, I am Peter Lio. I'm a clinical assistant professor of dermatology and pediatrics at Northwestern University Feinberg School of Medicine in Chicago, Illinois. I'm also the founding director of the Chicago Integrative Eczema Center.

With increased attention on airborne and household chemical exposures—such as detergents, pollutants, and volatile organic compounds—which exposures do you believe warrant the closest clinical scrutiny?

Dr Lio: I think we have to really review a lot of the things we're exposed to. I do feel like our food is important, and again, not so much that you're allergic to this food, but boy, this fabulous book, Dr Dawn Sherling wrote a book all about food and what parts of it can be unhealthy. And it sort of came about. She writes in the, I believe in the blurb or in the introduction about how many people, and we've all heard this, people say, when I go outside of the us, if I'm in Europe, I can eat bread and I can drink wine and I don't feel sick. When I come back to the us I eat certain things and I feel sick with those same foods. What's the difference? And it's probably multifactorial, but part of it seems to be the additives to food, the emulsifiers, the different preservatives, things that we put in our foods that really weren't there for most of human history.

So I think that some of the things we eat, these emulsion buyers, these different types of preservatives, they have an effect on our gut and on our microbiome in our gut. And that may be a really important piece of this whole puzzle. So everybody kind of blames gluten as being the enemy. And it may be for some people, certainly it is for some, but it may actually be more that the foods that gluten is in is actually part of the problem because it's processed in a way that's adding to this trouble. Of course, the air that we breathe, I'm a huge proponent, there's good pushback against electric vehicles. I understand that if people say, well, electric vehicles, it just means that a power plant's burning coal, a power agreed, but that power plant's not on my street belching the exhaust into my house, right? It's a little bit different.

We have the ability to control the emissions. In theory, we'd be able to use other forms of energy generation at a more central way or not. But I'm really interested in that. I think that emissions control is really important for little kids for asthma and other diseases. I think even thinking about our exposure to outside, there's been some really fascinating data looking at the development of myopia. So needing glasses and sun exposure and outdoor exposure seems to help prevent this. And I also wonder what are we missing by not being outside as much in terms of the microbiome, in terms of the vitamin D? Obviously as a dermatologist, I'm very careful about sun exposure. I don't want people to get too much, but too little is also bad. Most things in life have a curve where it's like the too much is bad, too little is bad, we have to get in the middle.
So I'm interested in all of these pieces in modern life, you realize that it exposes us to tons of pollutants and toxins. It locks us in indoor spaces where we're breathing things like our detergent. I was thinking about the other day when we're doing the laundry, we have a powdered detergent and this plume of detergent comes in the air, and I'm sitting here thinking, I'm in a tiny closed room that's sealed and I'm breathing this stuff in. So can we be more mindful about that? Can we bring more houseplant in? Can we open our windows a little bit more so that we're making sure that we're breathing fresh air and taking good care of all of those things around us? And I think that is dumb. As those things sound, they may actually be part of the issue.

Many patients with seasonal allergies report AD flares during high-pollen periods. What mechanisms best explain this pattern, and how can clinicians guide patients in proactively supporting their skin barrier?

Dr Lio: One fascinating thing about the body is that we'll see sometimes any kind of stimulus to the immune system can be more generalized. So the kind of classic example of this would be psoriasis and strep throat. People get strep throat infection and their psoriasis explodes. I don't think that strep is the cause of psoriasis, but it seems to be a very potent immune trigger. Of course, many of my patients with atopic dermatitis, if they get sick, they flare up. If they get a vaccine, a vaccine which is designed to stimulate your immune system, they can sometimes have a flare. I don't think they're allergic to the vaccine necessarily. That can happen too, but this is distinct and even for foods. So we do see this connection of things that stimulate the immune system in any way can cause these flareups. And I think pollen may be something similar.

So people, if they have even a low grade pollen allergy, once you start stimulating that immune response in your airway, that can generalize then and now it can sort of trigger an urticaria type response. People start scratching that triggers the eczema. So we see these vicious loops all over the place, and it's really tough. What do you tell a patient except you kind of just have to stay on top of it If it really seems to be primarily airway, can we do things like have a filter in the house? Can we make sure that their asthma is under good control? Can they take antihistamines if it's more of a rhinitis thing to help prevent that whole thing from starting? And if they do develop an eczema flare, I'm a huge believer that nipping it in the bud is the secret of success. You want to treat aggressively cool it down and break the cycle because once you let it escalate, much harder to control, much more expensive, more medicines needed. If you can stop it early, you break the cycle and get back to normal more quickly.

There is growing interest in the interplay between environmental exposures, microbial dysbiosis, and immune activation. How should allergists interpret these relationships when evaluating patients with AD?

Dr Lio: I think right now, cautiously, I think we understand the microbiome is playing a huge role, and I'm super excited about the pipeline. We have a number of therapies being developed that are ideally going to be able to manipulate the microbiome in a much more sophisticated way because I feel like this is a lever that we don't have access to. We can't pull the lever of, can we fix the microbiome in a gentle way? We have antiseptics and antibiotics and all these things, but this is not the ideal way to do this In our probiotic technology and prebiotics, symbiotics, postbiotics, the whole set of those things is in its infancy. So I feel like we're kind of like we're kids playing in the park still. We don't have any sophisticated way to do anything, but we're getting there and there are some breakthroughs happening. So right now, I think it's just important to acknowledge it.

It'd be weird in 2025, almost 2026, to say to a patient, oh, that has nothing to do with it. That's a bunch of baloney. That's bizarre. Although 10 years ago, I think you heard more people say the microbiome, I don't know, probiotics. It's a bunch of baloney now. I think we know it's not, but I do not think that we have any great answers. And I'm always very wary of people who are confident about it. They'll say, oh, we did a special kind of a gut microbiome test. Now we know exactly what's going on and we know how to fix it. I'm like, really? How do you know you're getting a sample that has a lot of variability from the colon that doesn't tell us anything? What's higher up? It's a point score. To me, there's way too many questions to feel confident. Now, is this how we build towards the future?

Sure. May some of these people be onto the right path. Absolutely. I encourage that. But you got to publish it. You have to refine it. We have to test it because otherwise, I mean, it just becomes somebody's opinion or somebody's idea and speculation. And that's not the best way to practice, especially in an area where we now do have some really well-studied treatments. So as an adjunct, you can play, but I feel bad when I have families who say, well, we don't want to use anything conventional. We're trying to work on just the gut. And I'm like, well, good luck. I don't have many tools to work on. Just your gut at this point, and you're coming to me with your skin is open and oozing and bleeding. So to say that it's all in the gut, it's a weird disbelief of reality. It's both in the gut, sure, but it's also on your skin, otherwise you wouldn't be at the dermatology office today.