Steven R. Feldman, MD, PhD
Another study caught my attention this month for having presented a lot of information with no clinically important conclusions. In "Mode of Delivery and Offspring Atopic Dermatitis in a Swedish Nationwide Study," Mubanga and colleagues studied 1.4 million children! With that many participants, they were almost certain to find associations that were statistically significant and clinically irrelevant. They reported that children born by instrumental vaginal delivery, emergency caesarean section, and elective caesarean section were at a higher risk for AD compared with those born by uncomplicated vaginal delivery. They failed to report the absolute magnitude of the associations, which were undoubtedly so small as to be clinically meaningless. Even if the observed association were not due to some hidden bias, the association is not anything that would change treatment in any way.
On the other hand, the small, open label registry analysis, "Experiences From Daily Practice of Upadacitinib Treatment on Atopic Dermatitis With a Focus on Hand Eczema: Results From the BioDay Registry," published by Kamphuis and colleagues , is of much greater value, reporting the effectiveness and safety of upadacitinib on hand eczema. Not surprisingly, there were large improvements in the investigators' assessments of the dermatitis and in patients' quality of life. This small study is informative about efficacy; it is too small, though, to evaluate how frequently rare severe adverse events occur.
The use of probiotics to safely improve skin disease is such an appealing concept, yet it sounds a lot like hocus-pocus to me. Feíto-Rodríguez and colleagues report in the journal Clinical and Experimental Dermatology that a probiotic mixture of Bifidobacterium lactis , Bifidobacterium longum, and Lactobacillus casei improved atopic dermatitis more than did placebo. The findings are not compelling. Differences were small. Rates of being clear or almost clear weren't reported. We can get atopic dermatitis to clear up in a few days with topical triamcinolone (if we can get patients to use it); so far, the effects of probiotics on the presumed gut-immune system-skin axis seem very much underwhelming.