AD Severity Linked to More Frequent Bathing, Not Duration

The frequency of showering or bathing and follow-up application of moisturizer appear to be more important factors associated with atopic dermatitis (AD) severity than the duration of showers or baths, results from a prospective observational study found.

Dr Uros Rakita

“Patients may benefit most from counseling on showering or bathing once daily and regularly applying moisturizer after showering or bathing,” one of the study authors, Uros Rakita, MSc, told this news organization. “Recommending less than daily shower frequencies or counseling on specific shower durations may not be necessary.”

During a late-breaking abstract session at the Revolutionizing Atopic Dermatitis Virtual Conference, Rakita, a fourth-year student at the Chicago Medical School at Rosalind Franklin University in North Chicago, Illinois, presented findings from a prospective, practice-based dermatology study that investigated the longitudinal relationship between different bathing practices and AD severity to help inform patient counseling about optimal bathing practices.

“AD is a chronic, inflammatory skin condition with a diverse set of environmental triggers and exacerbating factors,” Rakita said during the meeting. “Maintaining adequate skin hydration, skin hygiene, and avoiding triggers are key aspects of AD management across all disease severities. Therefore, understanding optimal shower or bath and moisturizing practices is essential.” In fact, he added, “bathing has been shown to not only hydrate the skin, but also to improve symptoms, remove allergens, and decrease S aureus colonization. However, at the same time, concern exists for the potential of inappropriate shower or bathing frequency or durations, as well as inconsistent moisturizer application to worsen disease severity and potentially compromise disease management.”

He noted that current guidelines on bathing frequency and duration among AD patients lack consensus, are limited, and are largely based on studies of pediatric populations.

Rakita, along with primary study author Jonathan I. Silverberg, MD, PhD, MPH, director of clinical research in the division of dermatology at George Washington University School of Medicine and Health Sciences, Washington, DC, and Trisha Kaundinya, a medical student at Northwestern University Feinberg School of Medicine, Chicago, Illinois, prospectively evaluated 509 adults with AD who made an average of 2.3 visits at a single dermatology clinic between 2013 and 2020. At each visit, severity of AD signs and symptoms, as well as bathing and moisturizing practices, were assessed.

AD severity was assessed using the objective component of Scoring Atopic Dermatitis (o-SCORAD), intensity of pruritus in the past 3 days (SCORAD-itch), Eczema Area and Severity Index (EASI), Patient-Oriented Eczema Measure (POEM), and Dermatology Life Quality Index (DLQI). The researchers constructed repeated measures regression models to examine associations of bathing and moisturizing practices with change in AD severity outcome measure scores over time. Multivariable models controlled for age, sex, and race.

In adjusted linear regression models, showering or bathing more than once a day vs once daily was associated with significantly higher scores for SCORAD-itch (0.74; P = .0456), o-SCORAD (4.27; P = .0171), EASI (4.20; P = .0028), POEM (2.61; P = .0021), and DLQI (2.77; P = .0004).

The researchers also found that consistent application of moisturizer after the shower or bath was associated with significantly lower scores for o-SCORAD (-7.22; P < .0001), EASI (-3.91; P = .001) and POEM (-2.68; P = .0002), compared against not applying moisturizer after a shower or bath. However, shower or bath duration of more than, compared against fewer than, 15 minutes was not associated with significantly lower scores for o-SCORAD (1.26; P = .2868), SCORAD-itch (0.17; P = .4987), EASI (0.85; P = .3454), POEM (0.24; P = .6627) or DLQI (-0.40; P = .4318).

“Interestingly, this pattern was present when the reference shower or bath durations were under 10 minutes as well as under 5 minutes,” Rakita said. “Also, shower or bath frequencies of less than daily, relative to daily frequencies, were not significantly related to longitudinal AD severity.”

Rakita acknowledged certain limitations of the study, including the fact that the researchers did not examine the potential influence of specific soap and moisturizing products, water hardness, or other bathing features such as water temperature and bath additives.

Lawrence J. Green, MD, who was asked to comment on the study, said that he was not surprised by the finding that moisturizing after bathing improved AD signs and symptoms. “On the other hand, a long-held belief that longer duration of shower/bath time worsens AD was not found to be true,” said Green, a dermatologist who practices in Rockville, Maryland, and is also clinical professor of dermatology at George Washington University, Washington, DC.

“This provides useful information for practicing dermatologists who wish to provide evidenced-based education about moisturizing and bathing to their AD patients,” he said.

The study was supported by the Agency for Healthcare Research and Quality and the Dermatology Foundation. Dr Silverberg disclosed that he is a consultant to numerous pharmaceutical companies, receives fees for non-CME/CE services from Eli Lilly, Leo Pharma, Pfizer, Regeneron Pharmaceuticals, and Sanofi Genzyme, as well as contracted research fees from Galderma. Dr Green disclosed that he is a speaker, consultant, or investigator for numerous pharmaceutical companies. There were no other disclosures.

Doug Brunk is a San Diego-based award-winning reporter for MDedge and Medscape who began covering healthcare in 1991. He is the author of two books related to the University of Kentucky Wildcats men’s basketball program.

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