Clinical Edge Journal Scan

Commentary: New and old treatments for AD, November 2023

Dr. Feldman scans the journals, so you don’t have to!

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Steven R. Feldman, MD, PhD

The study by Johnson and colleagues , "Prevalence of Allergic Contact Dermatitis in Children With and Without Atopic Dermatitis," has some good data on the frequency of positive patch test results in children with and without atopic dermatitis. The bottom line, as I see it, is that positive patch tests are not common in children, on the order of 2%. The most common allergens were nickel, fragrance, and preservatives. It may be good to have our patients avoid those. The authors concluded, perhaps because there was a "significantly" higher rate of positive patch tests in children with atopic dermatitis compared with those without, that there's a need for children with atopic dermatitis to be referred to a specialist for evaluation of contact allergy. But with only 2% of these patients having positive patch test results (and almost no difference [0.4%] between those with and those without atopic dermatitis), it might have been just as reasonable to conclude that such referrals are generally not needed unless there's a high level of suspicion that some unexpected allergen is causing a problem.

Flohr and colleagues present the results of a controlled trial of cyclosporine vs methotrexate for severe atopic dermatitis ("Efficacy and Safety of Ciclosporin Versus Methotrexate in the Treatment of Severe Atopic Dermatitis in Children and Young People"). Cyclosporine worked faster, yet methotrexate was a bit more effective in the long run. Both treatments had considerable side effects; 10% and 14% had serious events with cyclosporine and methotrexate, respectively. My only quibble is with the first word of the abstract background section; the authors call cyclosporine and methotrexate "conventional" systemic drugs for atopic dermatitis. At this point, considering safety and efficacy, I would consider drugs like dupilumab to be the "conventional" systemic treatment for atopic dermatitis.

Wan and colleagues ("Neuropsychiatric Disorders in Adults With Atopic Dermatitis") present an exceptionally well-done study with a huge patient population. The study compared about 600,000 adults with atopic dermatitis vs over 2,000,000 adults without the disease. A sample size like that offers a lot of power to detect very small differences between groups. The researchers report higher rates of anxiety and depression in patients with atopic dermatitis compared to those without. Are those differences clinically meaningfully different? The rates of depression were 14 and 17 cases per 1000 patient-years for those without and those with severe atopic dermatitis, respectively. That's a difference of 3 per 1000 patient-years. So maybe roughly 300 patients with atopic dermatitis would need to be seen to observe one patient with depression due to atopic dermatitis (assuming that the observed differences in rates between those with and those without atopic dermatitis were due to the dermatitis). The authors conclude, "Clinicians should inquire about mental health in patients with AD." I don't think their data support such a conclusion. We'd need to see a cost-effectiveness study to know if that's an intervention that we should do. Given the very small difference between the rates in those with and those without atopic dermatitis, it might be reasonable to conclude that we should inquire about mental health in patients with atopic dermatitis about as much as we should in patients without atopic dermatitis.

Some years ago, there was an over-the-counter topical product for psoriasis based on a banana peel extract. I think it was marketed as "FDA approved" for psoriasis (which was legal to say because the product also contained tar) and as being as effective as topical calcipotriene as published in the Journal of Investigational Dermatology (JID). I went to look for the article; the "publication" was the abstract of a poster presentation. The study followed a very small study population for a short period of time. The study was, I believe, underpowered to detect differences between the banana peel extract and the vitamin D analog. Those data were presented as a poster, the poster abstracts were printed in JID, and, voilà, the product was marketed as being as effective as topical calcipotriene as published in JID.

Sowlati and colleagues ("Efficacy and Tolerability of a Novel Topical Treatment Containing Pea Protein and Xyloglucan in the Management of Atopic Dermatitis in Children") randomly assigned 42 patients to receive either a xyloglucan/pea protein topical therapy or hydrocortisone. The participants were followed for 2 weeks. Both groups improved. We don't know whether they improved more than they would have with moisturizer. This study doesn't make me excited about prescribing the xyloglucan/pea protein topical.

The study by Mohamed and colleagues comparing tacrolimus and hydrocortisone reminds me that we have an effective generic topical anti-inflammatory for our patients with atopic dermatitis. Given the safety of topical tacrolimus, I prefer prescribing the 0.1% ointment for all my patients, though I give the lower concentration, approved for children, if the insurer makes me.

Simpson and colleagues' post hoc analysis of tralokinumab tells us that, with continued use, some patients who don't respond well initially will have greater improvement. But what I'd really like to see is a head-to-head study comparing tralokinumab vs dupilumab. Dupilumab seems to have stronger efficacy based on their reported trial numbers, but a head-to-head trial would give us greater confidence in their relative benefits.

I have trouble getting excited about this study by Cork and colleagues ("Dupilumab Safety and Efficacy in a Phase III Open-Label Extension Trial in Children 6-11 Years of Age With Severe Atopic Dermatitis"). I feel very comfortable with dupilumab already.

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