Peter A. Lio, MD: Atopic dermatitis is incredibly common, and it depends a little on how you ask the question and where in the world you ask the question. It’s much more commonly seen in areas that are more developed and less commonly seen in areas that are still developing or are more rural. This is an interesting question. In general, the estimates are that 15% to 20% of children are affected by this disease. It’s incredibly common. In adults, we’ve seen numbers ranging from 3% to 10%. So how you ask the question and where you ask it matter. The numbers I’ve seen in the United States are that an estimated 30 million people suffer from atopic dermatitis. That’s a lot of people.

When we look at that more moderate to severe group—if you take all comers, it could include people with mild stuff who maybe aren’t quite as germane to this conversation. As we look at the moderate to severe, for ages 6 and older, it’s estimated that over 2 million people have moderate to severe disease but aren’t doing well too because there’s a very powerful correlation with disease severity. It’s inversely correlated with treatment satisfaction. When we talk about severity, functional severity is important too. Somebody could look mild, but everything I’m doing is failing. I’m thinking, “My goodness, you’re mild-looking, but your eczema is behaving more like a severe case.” That’s important to think about as well.

Atopic dermatitis has some of the most burden that I see of any disease. There’s so much morbidity or suffering. The crazy thing is that it’s not just the patient who suffers. It’s their family unit, other caregivers, friends, and schoolwork. It has a rippling outward effect on people because it takes a terrible toll. Not only does it look bad, but patients feel self-conscious and embarrassed about their skin, especially when it’s in visible places. It’s also very uncomfortable. The itch drives people crazy.

We know to also ask about skin pain. Many patients have not only itchy but painful skin, which we know is terrible. Of course, it affects sleep. There’s a push in society—people are obsessed with getting good sleep. There are sleep trackers, and people are more aware of their sleep hygiene routines. Imagine if you had a condition that directly interfered with your sleep. Now all those things you’re trying to do to help you sleep are working against you. That’s important as well and makes it very tough for these patients. We can see it continue to ripple outward. There are financial issues that happen with this, and there’s absenteeism from work and school. Another term I love is “presenteeism,” which means you’re there, you’re not counted as absent, but you’re not there because you’re distracted, exhausted, and unfocused. It’s hard to measure that. All these pieces of the puzzle go into creating a tremendous burden of disease for these patients.

There are several groups of comorbidities that we think about with atopic dermatitis. The most common ones are allergic or atopic comorbidities. The ones that run very closely alongside would be things like asthma, food allergy, and allergic rhinitis. These run with atopic dermatitis. It’s fallen out of favor now, but people used to talk about the allergic march where people would start with atopic dermatitis, then develop a food allergy, then develop asthma, then develop rhinitis. But we know very few people. Probably less than 5% of patients go through those stages that way; they’re just associations.

Then there are a host of nonallergic or nonatopic comorbidities still being fleshed out. These include things like ADHD [attention-deficit/hyperactivity disorder]. We have growth and development problems in other ways. We even see things like cardiovascular disease in some studies that seem to be elevated. Other risk factors may have a more circuitous connection to the disease or one that we don’t fully understand, but they do seem to add to this overall burden, and it brings along with it other unwelcome guests.

Transcript edited for clarity.