Summarizing Key Updates in Contact Dermatitis Management 2026, With Walter Liszewski, MD

At the 2026 Maui Derm Hawaii conference at the Grand Wailea Hotel, a session titled ‘Contact Dermatitis Update 2026’ highlighted the evolving challenges of diagnosing and managing contact dermatitis.1 Presented by Walter Liszewski, MD, associate professor of dermatology and cancer epidemiology at Northwestern University’s Feinberg School of Medicine, this session emphasized several key points, including noting the limitations of existing patch-testing Core Series panels.2

In his interview with HCPLive’s editorial team, Liszewski spoke about these key takeaways from the session, addressing common diagnostic pitfalls and stressing the importance of distinguishing allergic contact dermatitis from atopic dermatitis, given that targeted biologic therapies for atopic disease may not improve allergic etiologies. These points and others are highlighted in this Q&A transcript of his interview:

HCPLive: Dr. Liszewski, thanks so much for taking the time to speak with us today. Firstly, what are the most important changes or updates from the past year that you feel are important for clinicians to recognize?

Liszewski: It's a couple of different things. First is that in patch testing, we have different ‘Core Series.’ These are allergens that we set nationally for the US and Canada that will catch the most common allergens. But they're not updated annually. What we start to see is that, in between the periodic updates, which occur every three to five years, there may be new allergens that are all of a sudden becoming very relevant. A couple of these that I emphasize, the big one is benzisothiazolinone.

It is not in the American contact dermatitis series, nor is it in the T.R.U.E. TEST. It's structurally similar to methylisothiazolinone and methylchloroisothiazolinone. Benzisothiazolinone is used predominantly in hand soaps, dish soaps, and laundry detergents. But it's less problematic. So many dermatologists may not have heard of benzisothiazolinone, let alone know how to counsel their patients about it. So, if you have a patient with recalcitrant hand dermatitis or weird rashes on their hands and arms, be sure to look at their hand soap, look at their dish soap, and make sure it does not contain benzisothiazolinone.

HCPLive: We know you discussed a range of dermatitis dilemmas. What were some of the most challenging or commonly mismanaged scenarios that you highlight?

Liszewski: There are two major ones. The first is chronic hand eczema. Chronic hand eczema is not atopic dermatitis. It can be in some circumstances, but for many patients with chronic hand eczema, they have a multifactorial cause of their dermatitis. There's allergic contact dermatitis, there's irritant contact dermatitis, and there can also be atopic dermatitis, but more often than not, it's multifactorial. The pearls I give [include one suggesting] that if you have a patient with chronic hand eczema, start with a prescription topical, but if that's still not working, then you should consider doing patch testing to make sure that there's not an allergenic cause.

The second thing I talk about is chronic lip dermatitis or colitis; more often than not, it's not an allergy. You can do patch testing, but you're probably not going to find anything. Most cases of chronic lip dermatitis are due to irritants. They're due to chronic lip licking. They're due to using too many skin care products. What patients in this group really benefit from is establishing a new treatment regimen. Simplify their products down, switch to thick barrier creams like Vaseline or Aquaphor, and try to pivot to using more hypoallergenic toothpaste in skincare products.

HCPLive: Were there any allergens, exposures, or patient behaviors that you emphasized as increasingly relevant in 2026?

HCPLive: I think the big thing is [regarding] gel nails and acrylic nails, but predominantly gel nails. Gel nails have been very popular in the past couple of years, but there have been numerous new at-home kits. They're excellent, so consumers are doing them more at home. The issue is that, historically, the major allergen in gel nails was something called 2-Hydroxyethyl methacrylate or HEMA. It's part of a larger group of adhesives called methacrylates. The issue is that the industry is now starting to use all kinds of different methacrylates. If you have a patient who comes in with allergies, and you suspect that there's an allergy to their acrylic or gel nails, if you're only testing with a standard series, which would be the ACDS Core Allergen Series or the North American Core, you're only going to be testing for Hydroxyethyl methacrylate.

The T.R.U.E. TEST does not even test for Hydroxyethyl methacrylate. So, if you have a patient like this, and you have a very high suspicion for a gel nail allergy, and they didn't react to HEMA, there's a good chance they were reacting to a different methacrylate. As someone who does extended patch testing, I have an additional 20 methacrylates I can test. I routinely test on an extended tray to make sure I'm not missing any methacrylate allergies. But if you're someone who doesn't have that available, it's just important to remember that HEMA, although it catches many forms of gel nail allergies, given that there's so much heterogeneity currently in the market for the glues that companies are using, it may not catch all cases.

HCPLive: How did you recommend clinicians refine their diagnostic approach when contact dermatitis overlaps with atopic or other inflammatory diseases?

HCPLive: It's difficult. The challenging thing is that for atopic dermatitis, there is no diagnostic test, but for allergic contact dermatitis. So if you have a patient with moderate to severe eczema and it's not improving with topicals, those patients are candidates for patch testing. If you find an allergy and they get better, you know that there was either an exclusive allergic reaction or part of the dermatitis was due to allergies. However, if you do patch testing and there are no allergens, then you know that their allergen is either irritant dermatitis or exclusively atopic dermatitis in nature. The reason why that's important is that many of the drugs we use to treat atopic dermatitis, like lebrikizumab or dupilumab, will not be effective for most forms of allergic contact dermatitis. So identifying a precise cause is very important, because not all treatments will work for all forms of eczema.

HCPLive: If clinicians could take away only one or two practice-changing points from your session, what would you want them to remember?

Liszewski: The first thing is, we always need more people to do patch testing. And I'm someone who specializes in advanced patch testing. I have 500 allergens in my clinic. I routinely test patients for more than 100 allergens. Technically, yes, that is the ideal way it should be done. But that's not the only way that needs to be done. And if you're someone who can only do the American contact dermatitis 90 allergens, or even just the T.R.U.E. TEST, it can still be helpful. We need more dermatologists who are willing and capable of doing patch testing, because it can be transformative for many of our patients with chronic eczematous dermatitis.

The second thing that I would emphasize is that you need to read labels. One thing that I encourage all of you to do is next time you're at the grocery store, you're at a pharmacy, and you're looking at shampoos or lotions, look at a bunch of them. Look at the ingredients. Are there new chemicals you haven't seen before? Are there certain chemicals that you used to see all the time, like methylisothiazolinone, that just aren't there anymore, or methyldibromo glutaronitrile? Some chemicals become popular, and then they go away. I think it's very important for us to know what are the chemicals that our patients are coming in contact with, so that we can better identify potential causes and tailor our patch testing to their needs.

The quotes used in this summary were edited for the purposes of clarity.

Liszewski did not have any relevant disclosures of note.

References

1. Liszewski W. Contact Dermatitis Update 2026. Presented at: Maui Derm Hawaii 2026; January 25-29, 2026; Maui, Hawaii.

2. Schalock PC, Dunnick CA, American Contact Dermatitis Society Core Allergen Series Committee, et al. American Contact Dermatitis Society Core Allergen Series: 2020 Update. Dermatitis. 2020 Sep-Oct;31(5):279-282. doi: 10.1097/DER.0000000000000621. PMID: 32947457.