Dr. Jonathan Silverberg discusses the overlap of atopic dermatitis with allergic or irritant dermatoses and differentiating forms of eczema for optimal patient care.
Jonathan Silverberg, MD, PhD, MPH, is Professor of Dermatology and Director of Clinical Research and Patch Testing, George Washington University School of Health Sciences, Washington, DC
“Dermatitis in the broadest sense or even eczematous morphology is just that—morphology. It’s a visual pattern, something that we see either with the naked eye or looking under a microscope at histological patterns,” said Jonathan Silverberg, MD, PhD, MPH, who presented “Diagnosis and Management of Non-Atopic Forms of Dermatitis in Atopic Dermatitis Patients” at the International Eczema Council satellite meeting at AAD 2022.
“But there are many different etiologies for eczematous disorders. And we certainly should not assume that all forms of eczema are atopic dermatitis.”
Dermatologists have a broad differential diagnosis, in general, when differentiating atopic dermatitis from irritant contact dermatitis, allergic contact dermatitis, or nummular dermatitis, said Dr. Silverberg.
“But even in patients with established atopic dermatitis, there can be overlapping and confounding diagnoses where patients can have a superimposed irritant contact dermatitis, perhaps something occupationally related. Or they can have a superimposed allergic contact dermatitis, which often is related to personal care products but can be related to any number of different exposures. This occurs even within that patient who has well established and perhaps a lifelong history of atopic dermatitis.”
According to Dr. Silverberg, there isn’t necessarily a single site where non-atopic forms of dermatitis manifest in atopic dermatitis patients but having lesions in different sites should cause dermatologists to consider diagnoses other than atopic dermatitis.
“Certainly, very strong involvement of the hands will make us think about either irritant or allergic contact dermatitis as a potential trigger or additional diagnosis above and beyond the atopic dermatitis. Head and neck dermatitis is another site which prompts us to think about the prospect of allergic contact dermatitis. There can be head and neck dermatitis that is not related to allergic or irritant contact dermatitis, but it’s definitely a broad differential and something we should think about.”
In reality, any site on the body where there is localized predominance should prompt thinking about a possible irritant or allergic trigger. Another clue is something that behaves differently, said Dr. Silverberg.
It could be “Any scenario where we might have particularly refractory disease that just doesn’t seem to respond to topical therapy the way we would have expected. That may also suggest that there is some additional exogenous trigger like an irritant or allergen that may be perpetuating the disease.”
Symptoms of non-atopic forms of dermatitis can be the same or differ from a patient’s usual symptoms, said Dr. Silverberg.
“For many patients, all we are able to see and all our patients are able to appreciate is that their atopic dermatitis is more severe than it used to be or not responding to therapy. The symptoms may be no different than their baseline atopic dermatitis. But perhaps it’s behaving a little differently with respect to how persistent it is over time or how it responds to therapy.”
According to Dr. Silverberg, patients with irritant contact dermatitis may experience more pain or burning than itch.
“But that is not necessarily a hard and fast rule either. Irritant contact dermatitis as the underlying etiology can, in fact, have a major component of itch, as well.”
Is Non-Atopic Dermatitis a Comorbidity?
“Some may say it’s just semantics, but I don’t think it’s just semantics. Honestly, I’m not sure exactly what we should call it. But I think the most important thing we should recognize is the phenomenon—the pattern. Patients with atopic dermatitis, because of their immune predisposition and the barrier dysfunction that happens with the disease, are going to be more vulnerable to the outside world insults—the irritants and allergens, etc.”
It’s true that exacerbations from triggers, including stress, heat, sweat, and the dryness of winter, are part of atopic dermatitis. It’s also true that irritant contact dermatitis and allergic contact dermatitis are standalone diagnoses that happen in patients who have never had a day of atopic dermatitis in their lives, according to Dr. Silverberg.
“A common scenario I see with patients is they’ll get flexural eczema in the wintertime, but then they’ll get hand dermatitis that is present all year long. It follows a different timeline; it doesn’t respond to therapy as much. Maybe it has different symptoms. That should prompt us to say, wait a minute, this is different. It may look visually like their atopic dermatitis, but it’s not behaving like their atopic dermatitis.”
In a patient like that, Dr. Silverberg said he doesn’t think it’s just an allergic trigger or an irritant trigger of underlying atopic dermatitis, but rather a comorbid diagnosis.
Managing the Overlay
Managing non-atopic forms of dermatitis in atopic dermatitis patients is the same in some respects, but there are a few differences, said Dr. Silverberg.
“First and foremost, if there is something that is avoidable, we want to help patients identify it and avoid it. We want to help patients maximize the safest nonmedicated solutions where possible and wherever feasible.”
“When we do need to seek out pharmacologic therapy, there are treatment approaches largely consistent with how we would manage atopic dermatitis, where we’ll use topical corticosteroids or topical calcineurin inhibitors, some of the newer topical nonsteroidal agents, as well as phosphodiesterase-4 (PDE-4) inhibitors or topical Janus kinase (JAK) inhibitors would all be reasonable solutions in these scenarios.”
Dermatologists also might have to turn to advanced therapies, like phototherapy or oral systemic therapy, even biologic therapies for those more challenging and refractory cases, he said.
“But while we see that those treatments tend to work quite well across this range of the simple atopic dermatitis as well as the atopic dermatitis that overlaps with irritant and allergic contact dermatitis, I don’t think it’s as simple as saying all therapies will work equally well in all patient subsets. A big part of future research will seek out better ways of identifying these patients—trying to get closer to a precision medicine approach where we’ll better understand which patients would do better with their allergic or contact dermatitis than others with respect to targeted therapies like biologics or when topical therapies will and won’t be adequate.”
Disclosures: Dr. Silverberg has received honoraria as a consultant and/or advisory board member for Abbvie, Afyx, Aobiome, Arena, Asana, Aslan, BioMX, Biosion, Bluefin, Bodewell, Boehringer-Ingelheim, Cara, Castle Biosciences, Celgene, Connect Biopharma, Dermavant, Dermira, Dermtech, Eli Lilly, Galderma, GlaxoSmithKline, Incyte, Kiniksa, Leo Pharma, Luna, Menlo, Novartis, Optum, Pfizer, RAPT, Regeneron, Sanofi-Genzyme, Shaperon, Sidekick Health, Union; speaker for Abbvie, Eli Lilly, Leo Pharma, Pfizer, Regeneron, Sanofi-Genzyme; institution received grants from Galderma and Pfizer.
