Atopic Dermatitis: Age of Onset and Prevalence

Transcript: Lawrence Eichenfield, MD: Hello, and welcome to this HCPLive® Peer Exchange titled, “Optimizing Treatment of Pediatric Atopic Dermatitis.”

I’m Dr Larry Eichenfield, from Rady Children’s Hospital—San Diego and the University of California, San Diego School of Medicine in San Diego, California.

Joining me for this discussion today are my colleagues Dr Fred Ghali, from Pediatric Dermatology of North Texas in Dallas, Texas; Dr Peter Lio from Northwestern University Feinberg School of Medicine in Chicago, Illinois, and Medical Dermatology Associates in Chicago; and Dr Elaine Siegfried from St Louis University School of Medicine and Cardinal Glennon Children’s Hospital in St Louis, Missouri. Also joining us later for some additional insight is Dr Amy Paller from Northwestern University Feinberg School of Medicine in Chicago.

In today’s discussion we will provide a brief overview of atopic dermatitis [AD] and its diagnosis and focus on recently approved treatment regimens for the pediatric population. Let’s get started.

We’re going to start with an overview on atopic dermatitis. Elaina, I’m going to turn to you. We discuss atopic dermatitis; we discuss eczema. Are those terms interchangeable for you? What’s your sense of how we should use those words in our normal dialogue?

Elaine Siegfried, MD: Dermatitis and eczema are synonyms, but there are a lot of different kinds of eczema, and there are even a few different kinds of atopic dermatitis. Dermatitis is just a phenotype. The most common kind of eczema is probably contact dermatitis, irritant before allergic. Atopic dermatitis is the most common chronic type of eczema in children.

Lawrence Eichenfield, MD: And what’s the typical age of onset of atopic dermatitis?

Elaine Siegfried, MD: It is sad, but in my practice the great majority present under age 2 years. About 80%, at least.

Lawrence Eichenfield, MD: Prevalence of atopic dermatitis. Peter, what’s your sense? There are lots of different data sets, but atopic prevalence in pediatric and adolescents. What’s your sense of the percentage of children who outgrow their disease?

Peter Lio, MD: It’s a moving target, it seems. We know that back in the 1940s and 1950s it was of much lower prevalence, and that’s going to continue to escalate to some degree. But when you look at the studies, it seems that in kids it’s somewhere between 10% and maybe as high as 20% in some populations; there’s some variability. When we think about adults, anywhere from 3% to 10% of them. Again, it depends on how you define it. That’s pretty important, because we know the burden on these patients is pretty significant. If you have a pretty big number like that, with a significant burden, then that number multiplies out to a lot of suffering.

Lawrence Eichenfield, MD: Yeah. I think some of the data are tricky, because we used to say that most kids outgrow their eczema, and then we find higher rates of eczema in adults now. Some are nuanced; some are persistent. But there are very few studies that actually follow individual groups of patients over time, and those studies—they were put together in a metanalysis—ended up with totally different conclusions about what percentage of people lost their eczema over time. So it’s tricky.

Let me ask Fred to discuss what he thinks the course of AD is from an individual perspective and then across groups of patients, and then we can discuss it as a group.

Fred Ghali, MD: From an individual perspective, it’s really unpredictable. I like to share with my families that it’s like a roller-coaster ride if you will. Often they have good days followed by bad days. If you look at some of the studies among our pediatric patients, some of them spend 1 of every 3 days in the mirror managing some type of flair. I always like to share that the course can be ups and downs. As far as across patient groups, we see some kids, as Elaine mentioned, who present very early in life, with onset in the first few months, and they may or may not outgrow the disease. Then we have other groups of patients who may develop atopic dermatitis after year 2 and throughout their adolescence period. Oftentimes, the groups may overlap, and the disease is chronic and unpredictable.

Lawrence Eichenfield, MD: There’s that paper that has these big longitudinal cohorts that they follow over time, and they basically said, “We like the simple story that it starts early and goes away.” But there are all these little sub bars: patients who present early and then it goes away, the classic; patients who present early and persist; patients who present later in childhood and persist; patients who present later in childhood and it gets better. Partially, in clinical practice, I saw just saw a patient yesterday, and she had new eczema, with some patchy eczema on the face and the neck, had a little bit of antecubital fossa involvement. It was a 13-year-old; it had been happening for about 4 months. For history, it took maybe 10 seconds of questioning to say, “She had eczema as a baby, she had patchy cheeks, and she had stuff on her antecubital and popliteal fossa.” She was just in prolonged remission for years essentially, for whatever trigger was now in a situation where she was more active.

I still give the same spiel, that within the first few years of life, you’ll probably outgrow your disease. But I feel a little guilty doing that, because I know it may be an oversimplification. I guess for the group, when do you get worried or get a sense that it may be more persistent disease that may keep going?

Elaine Siegfried, MD: One of the most frustrating things for patients is that we don’t have great predictors for who’s going to be persistent, who ultimately is going to require systemic therapy. There are a couple of things that have been looked at and published, like total IgE levels; it’s an easy thing to measure. Not an incredibly wonderful predictor in a subset, but sort of tends to be. It’s something people can use. I have found that early onset of allergic rhinitis is another predictor of severity of disease. Certainly family history and then other atopic morbidities are important ones to consider too.

Lawrence Eichenfield, MD: The allergic rhinitis is pretty common early. We did a prospective study, the pimecrolimus-versus-steroid study. It was an end phase, and we watched it for a few years of life. Almost one-third by age 2 had allergic rhinitis in that early onset group. That’s pretty consistent in other data sets as well. When you start to get to more severe patients it’s even higher. Real-food allergy is probably 40% for moderate to severe patients than mild patients. Those comorbidities really climb up.

Transcript Edited for Clarity