Skin absorption through atopic dermatitis skin: a systematic review

Allergic Contact Dermatitis in Children: Recommendations for Patch Testing

PURPOSE OF REVIEW

Allergic contact dermatitis (ACD) affects 20% of children. However, diagnosis of ACD may be underreported in children due to lack of recognition. Patch testing is the gold standard for evaluation of ACD in children but poses unique challenges in this population.

RECENT FINDINGS

Recent studies highlight the significance of ACD and the utility of patch testing in children. Evaluation of ACD in children is difficult and requires knowledge of a child's exposure history, careful selection of allergens, and knowledge of specialized patch testing considerations to minimize irritation and maximize cooperation. Until recently, there were no agreed upon patch test series for children. In 2018, a comprehensive pediatric baseline series was published enabling thorough evaluation of ACD in children (Yu J, Atwater AR, Brod B, Chen JK, Chisolm SS, Cohen DE, et al. Dermatitis. 2018;29(4):206-12). This review provides an overview of the current literature, an update on pediatric ACD, and patch testing methods in children to effectively evaluate and manage ACD.

Behavior of 1-Deoxy-, 3-Deoxy- and N-Methyl-Ceramides in Skin Barrier Lipid Models

Ceramides (Cer) are essential components of the skin permeability barrier. To probe the role of Cer polar head groups involved in the interfacial hydrogen bonding, the N-lignoceroyl sphingosine polar head was modified by removing the hydroxyls in C-1 (1-deoxy-Cer) or C-3 positions (3-deoxy-Cer) and by N-methylation of amide group (N-Me-Cer). Multilamellar skin lipid models were prepared as equimolar mixtures of Cer, lignoceric acid and cholesterol, with 5 wt% cholesteryl sulfate. In the 1-deoxy-Cer-based models, the lipid species were separated into highly ordered domains (as found by X-ray diffraction and infrared spectroscopy) resulting in similar water loss but 4–5-fold higher permeability to model substances compared to control with natural Cer. In contrast, 3-deoxy-Cer did not change lipid chain order but promoted the formation of a well-organized structure with a 10.8 nm repeat period. Yet both lipid models comprising deoxy-Cer had similar permeabilities to all markers. N-Methylation of Cer decreased lipid chain order, led to phase separation, and improved cholesterol miscibility in the lipid membranes, resulting in 3-fold increased water loss and 10-fold increased permeability to model compounds compared to control. Thus, the C-1 and C-3 hydroxyls and amide group, which are common to all Cer subclasses, considerably affect lipid miscibility and chain order, formation of periodical nanostructures, and permeability of the skin barrier lipid models.

Twenty Clinically Pertinent Factors/Observations for Percutaneous Absorption in Humans

At least 20 clinically relevant factors affect percutaneous absorption of drugs and chemicals: relevant physico-chemical properties, vehicle/formulation, drug exposure conditions (dose, duration, surface area, exposure frequency), skin appendages (hair follicles, glands) as sub-anatomical pathways, skin application sites (regional variation in penetration), population variability (premature, infants, and aged), skin surface conditions (hydration, temperature, pH), skin health and integrity (trauma, skin diseases), substantivity and binding to different skin components, systemic distribution and systemic toxicity, stratum corneum exfoliation, washing-off and washing-in, rubbing/massaging, transfer to others (human to human and hard surface to human), volatility, metabolic biotransformation/cutaneous metabolism, photochemical transformation and photosensitivity, excretion pharmacokinetics, lateral spread, and chemical method of determining percutaneous absorption.

Effects of omega-O-acylceramide structures and concentrations in healthy and diseased skin barrier lipid membrane models

Ceramides (Cers) with ultralong (∼32-carbon) chains and ω-esterified linoleic acid, composing a subclass called omega-O-acylceramides (acylCers), are indispensable components of the skin barrier. Normal barriers typically contain acylCer concentrations of ∼10 mol%; diminished concentrations, along with altered or missing long periodicity lamellar phase (LPP), and increased permeability accompany an array of skin disorders, including atopic dermatitis, psoriasis, and ichthyoses. We developed model membranes to investigate the effects of the acylCer structure and concentration on skin lipid organization and permeability. The model membrane systems contained six to nine Cer subclasses as well as fatty acids, cholesterol, and cholesterol sulfate; acylCer content-namely, acylCers containing sphingosine (Cer EOS), dihydrosphingosine (Cer EOdS), and phytosphingosine (Cer EOP) ranged from zero to 30 mol%. Systems with normal physiologic concentrations of acylCer mixture mimicked the permeability and nanostructure of human skin lipids (with regard to LPP, chain order, and lateral packing). The models also showed that the sphingoid base in acylCer significantly affects the membrane architecture and permeability and that Cer EOP, notably, is a weaker barrier component than Cer EOS and Cer EOdS. Membranes with diminished or missing acylCers displayed some of the hallmarks of diseased skin lipid barriers (i.e., lack of LPP, less ordered lipids, less orthorhombic chain packing, and increased permeability). These results could inform the rational design of new and improved strategies for the barrier-targeted treatment of skin diseases.

Staphylococcal Virulence Factors on the Skin of Atopic Dermatitis Patients

For the first time, we show that secreted staphylococcal virulence factors can be quantified at the protein level directly from skin swabs obtained from the skin of atopic dermatitis patients. This technique eliminates the need to culture Staphylococcus aureus and then test the strain’s potential to produce secreted virulence factors. Our methodology shows that secreted virulence factors are present on the skin of atopic patients and provides a more accurate means of evaluating the physiological impact of S. aureus in inflammatory diseases such as atopic dermatitis.

Staphylococcus aureus is the leading cause of skin and soft tissue infections, bacteremia, infective endocarditis, osteoarticular, pleuropulmonary, and device-related infections. Virulence factors secreted by S. aureus, including superantigens and cytotoxins, play significant roles in driving disease. The ability to identify virulence factors present at the site of infection will be an important tool in better identifying and understanding how specific virulence factors contribute to disease. Previously, virulence factor production has been determined by culturing S. aureus isolates and detecting the mRNA of specific virulence factors. We demonstrated for the first time that virulence factors can be directly detected at the protein level from human samples, removing the need to first culture isolated bacteria. Superantigens and cytotoxins were detected and quantified with a Western dot blot assay by using reconstituted skin swabs obtained from patients with atopic dermatitis. This methodology will significantly enhance our ability to investigate the complex host-microbe environment and the effects various therapies have on virulence factor production. Overall, the ability to directly quantify virulence factors present at the site of infection or colonization will enhance our understanding of S. aureus-related diseases and help identify optimal treatments.

IMPORTANCE For the first time, we show that secreted staphylococcal virulence factors can be quantified at the protein level directly from skin swabs obtained from the skin of atopic dermatitis patients. This technique eliminates the need to culture Staphylococcus aureus and then test the strain’s potential to produce secreted virulence factors. Our methodology shows that secreted virulence factors are present on the skin of atopic patients and provides a more accurate means of evaluating the physiological impact of S. aureus in inflammatory diseases such as atopic dermatitis.

Prediction of the skin permeability of topical drugs using in silico and in vitro models

The main challenge of topically applied drugs is to overcome the skin barrier to reach the site of action at the concentration needed for efficacy. In the research of new topical drugs, design of molecules with optimized properties for skin penetration is a key factor and assays for its characterization are needed. A group of 20 representative topical molecules of clinical use were studied in two in silico models (Potts & Guy and Barratt), and an in vitro assay with artificial membrane (Skin-PAMPA). A subset of 9 drugs were also evaluated in the Franz cells assay, formulated in a solvent and in a marketed formulation. Each assay allowed us to grade compounds according to their permeability value. Globally good alignments were found for the studied compounds when comparing models, although discrepancies for some compounds such as tazarotene, tacrolimus, ketoconazole and metronidazole were observed. Overall, the studied in silico and the in vitro models are useful tools to support selection and characterization of research compounds in terms of skin permeability.

Comorbidities and the impact of atopic dermatitis

OBJECTIVE

Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disease with substantial patient and population burdens. A number of comorbid health problems occur in patients with AD, aside from the cutaneous signs and symptoms. This review summarizes recent developments in the burden and comorbidities of AD.

DATA SOURCES

Literature review.

STUDY SELECTIONS

Nonsystematic.

RESULTS

Different aspects of AD, such as chronic pruritus, psychosocial distress, and inflammation, can lead to anxiety, depression, or suicidality. Atopic dermatitis is associated with and may predispose to higher risk of other atopic disorders, including asthma, hay fever, food allergy, and eosinophilic esophagitis. Persons with AD appear to be at higher risk for infectious and cardiovascular risk.

CONCLUSION

Atopic dermatitis is associated with substantial burden and comorbidities. Identifying AD comorbidities is essential for proper disease management and improving overall patient outcomes.

Urinary excretion of phenols, parabens and benzophenones in young men: Associations to reproductive hormones and semen quality are modified by mutations in the Filaggrin gene

BACKGROUND

The filaggrin gene (FLG) encodes an epidermal protein, filaggrin, which is important for normal skin barrier functions. We previously showed that FLG loss-of-function mutation carriers have a higher internal exposure to some non-persistent chemicals such as certain phthalates and parabens, suggesting increased trans-epidermal penetration. Several groups of non-persistent chemicals are suspected endocrine disrupters with potential to affect testicular function.

OBJECTIVES

To investigate associations between exposure to non-persistent chemicals and testicular function in young Danish men with and without FLG mutations.

METHODS

We measured urinary concentrations of bisphenol A (BPA) and other simple phenols, parabens, and UV filters including benzophenones (BP-1, BP-3 and 4-HBP) in men genotyped for FLG R501X, 2282del4, and R2447X loss-of-function mutations; in total 65 mutation carriers and 130 non-carriers (controls) were included. Outcomes were markers of testicular function, assessed by serum reproductive hormones and semen quality.

RESULTS

We found that associations between urinary chemical concentrations and outcomes were different in cases and controls. Within the group of FLG mutation carriers, higher urinary concentrations of BPA, BP-1 and BP-3 were associated with higher testosterone and estradiol serum levels and lower FSH. Similar trends in hormone levels were observed for FLG mutation carriers with measurable levels of 4-HBP compared to those who had no detectable levels of urinary 4-HBP. Furthermore, those in the highest urinary BPA quartile had lower sperm motility than those in the lower quartiles. None of these associations were evident in the control group. In the control group, however, lower sperm motility and sperm concentration were observed in the men with detectable urinary 4-HBP compared to the men non-detectable urinary 4-HBP. We found no association between any parabens and outcomes, nor for the other measured phenols or UV filters.

CONCLUSIONS

Associations between male reproductive health parameters and urinary levels of BPA and benzophenones such as BP-3, BP-1 and 4-HBP were observed in FLG mutation carriers but not in controls from the same study population. This difference between FLG mutation carriers and non-carriers is not explained solely by differences in exposure levels of the examined compounds as e.g. BPA and 4-HBP urinary levels did not differ between the two groups. We hypothesise that effects of exposure to these compounds may be modulated in FLG mutation carriers by either different levels of co-exposures or by route of uptake, with a higher fraction of the uptake by dermal uptake.

[Influence of Bases for External Medicines with Different Coatability and Water Retentivity on Wound Healing]

When selecting external medicines for the treatment of skin diseases, it is thought to be very important to consider differences in characteristics of their bases, because the bases may influence the clinical efficacy of the medicines. In this study, we investigated whether the differences in characteristics of three kinds of bases, white petrolatum, macrogol ointment, and aqueous gel affect wound healing. In vitro moisture permeability tests demonstrated that these bases have different characteristics in coatability and water retentivity, with the rank order of the intensity of coatability as white petrolatum>macrogol ointment>aqueous gel, and that of water retentivity as macrogol ointment>white petrolatum>aqueous gel. Similar rank order of these bases was observed for transepidermal water loss and stratum corneum water content in the dry skin on the abdomen of guinea pigs induced by topical application of acetone/ether mixture, followed by water. In addition, we found that treatment with macrogol ointment, but not white petrolatum or aqueous gel, significantly accelerated wound healing in rat skin, and that the contents of basic fibroblast growth factor and epidermal growth factor in the skin treated with macrogol ointment were significantly higher compared with non-treated skin. In conclusion, these results imply an important role of the bases of external medicines in the treatment of skin diseases.

Atopic dermatitis

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease, with a lifetime prevalence of up to 20% and substantial effects on quality of life. AD is characterized by intense itch, recurrent eczematous lesions and a fluctuating course. AD has a strong heritability component and is closely related to and commonly co-occurs with other atopic diseases (such as asthma and allergic rhinitis). Several pathophysiological mechanisms contribute to AD aetiology and clinical manifestations. Impairment of epidermal barrier function, for example, owing to deficiency in the structural protein filaggrin, can promote inflammation and T cell infiltration. The immune response in AD is skewed towards T helper 2 cell-mediated pathways and can in turn favour epidermal barrier disruption. Other contributing factors to AD onset include dysbiosis of the skin microbiota (in particular overgrowth of Staphylococcus aureus), systemic immune responses (including immunoglobulin E (IgE)-mediated sensitization) and neuroinflammation, which is involved in itch. Current treatments for AD include topical moisturizers and anti-inflammatory agents (such as corticosteroids, calcineurin inhibitors and cAMP-specific 3',5'-cyclic phosphodiesterase 4 (PDE4) inhibitors), phototherapy and systemic immunosuppressants. Translational research has fostered the development of targeted small molecules and biologic therapies, especially for moderate-to-severe disease.

The Role and Diagnosis of Allergic Contact Dermatitis in Patients with Atopic Dermatitis

Patients with atopic dermatitis (AD) have increased penetration of allergens, immune dysregulation (including shared cytokine pathways), and frequent use of emollients and topical medications, all of which may predispose toward developing allergic contact dermatitis (ACD). Recent systematic reviews have suggested that ACD is a significant clinical problem in both children and adults with AD. While this remains controversial, ACD remains an important comorbidity and potential exacerbant of AD in clinical practice. Common relevant allergens, include lanolin, neomycin, formaldehyde, sesquiterpene lactone mix, compositae mix, and fragrances that are commonly found in AD patients' personal care products. We herein review the clinical scenarios where patch testing is indicated in AD. In addition, we review the contraindications, preferred patch-testing series, pitfalls, and challenges determining the relevance of positive patch-test reactions in AD patients.

Systemic Pharmacokinetics, Safety, and Preliminary Efficacy of Topical AhR Agonist Tapinarof: Results of a Phase 1 Study

Tapinarof cream is a novel topical nonsteroidal agent that represents a unique class of anti-inflammatory molecules targeting the aryl hydrocarbon receptor. Study 201851 was an open-label, 2-cohort sequential study that assessed the systemic pharmacokinetics, safety, and efficacy of tapinarof in adults with moderate to severe atopic dermatitis. A total of 11 participants were enrolled: 5 received 2% cream, and 6 received 1% cream. Tapinarof was systemically absorbed, and measurable amounts were detected in both cohorts. Generally, plasma exposure was greater with the 2% cream and decreased from day 1 to day 21. Median T_max ranged from 1 to 4 hours. Preliminary efficacy results were similar between the 1% and 2% concentrations, with the 1% cream showing better tolerability based on 3 subjects in the 2% cohort who discontinued treatment because of systemic AEs. The efficacy and safety of 1% tapinarof support results of previous positive studies that used a different formulation. However, conclusions in the present study are limited because of the open-label design and small number of participants. The 1% cream was selected as the concentration for use in future studies because of its lower AE incidence and efficacy comparable to the 2% cream.

Children with atopic dermatitis and frequent emollient use have increased urinary levels of low-molecular-weight phthalate metabolites and parabens

BACKGROUND

Parabens may be added to cosmetic and personal care products for preservation purposes. Low-molecular weight (LMW) phthalate diesters function as plasticizers, fixatives or solvents in such products, but may also be found in small quantities as contaminants from plastic containers.

OBJECTIVE

To evaluate the association between emollient use, atopic dermatitis and FLG mutations, respectively, with urinary concentrations of phthalate metabolites and parabens in Danish children.

METHODS

Eight hundred and forty-five Danish children 4-9 years of age were studied. Urinary concentrations of phthalate metabolites and parabens were determined, and children were genotyped for common FLG loss-of-function mutations. Information about atopic dermatitis and use of emollients was obtained from questionnaires completed by parents.

RESULTS

The prevalence of atopic dermatitis was 16.1%. Phthalate metabolite and paraben levels were generally higher in children with frequent use of emollients compared to uncommon users, reaching statistical significance for some LMW phthalates and parabens. While there was no association with common FLG mutations, children with atopic dermatitis had significantly higher urinary levels of one LMW phthalate and two parabens, respectively, when compared to children without atopic dermatitis.

CONCLUSION

Emollient use and atopic dermatitis were associated with modestly increased internal LMW phthalate and paraben exposure in 4-9 year old children. It is unknown whether the difference is explained by increased use of the specific emollients that are used to treat pruritic and inflamed skin, and/or whether the impaired skin barrier allows chemicals to penetrate more easily. Moreover, the putative toxicological burden is unknown.

Dermal Uptake of Benzophenone-3 from Clothing

Benzophenone-3 (also known as BP-3 or oxybenzone) is added to sunscreens, plastics, and some coatings to filter UV radiation. The suspected endocrine disruptor BP-3 has been detected in the air and settled dust of homes and is expected to redistribute from its original sources to other indoor compartments, including clothing. Given its physical and chemical properties, we hypothesized that dermal uptake from clothing could contribute to the body burden of this compound. First, cotton shirts were exposed to air at an elevated concentration of BP-3 for 32 days; the final air concentration was 4.4 μg/m³. Next, three participants wore the exposed shirts for 3 h. After 3 h of exposure, participants wore their usual clothing during the collection of urine samples for the next 48 h. Urine was analyzed for BP-3, a metabolite (BP-1), and six other UV filters. The rate of urinary excretion of the sum of BP-1 and BP-3 increased for all participants during and following the 3 h of exposure. The summed mass of BP-1 and BP-3 excreted during the first 24 h attributable to wearing exposed t-shirts were 12, 9.9, and 82 μg for participants 1, 2, and 3, respectively. Analysis of these results, coupled with predictions of steady-state models, suggest that dermal uptake of BP-3 from clothing could meaningfully contribute to overall body burden.

Emollients and moisturizers for eczema: abridged Cochrane systematic review including GRADE assessments

Eczema is a chronic inflammatory skin disorder with considerable impact on quality of life. Emollients or moisturizers are widely recommended, but are these effective and safe? We searched for randomized controlled trials (RCTs) in the Cochrane Skin Group Specialised Skin Register, CENTRAL in The Cochrane Library, MEDLINE, Embase, LILACS, the GREAT database and five trial registers to December 2015. We included 77 RCTs with 6603 participants. Seven studies (9%) were at low risk of bias, 34 (44%) had unclear risk and 36 (47%) were at high risk. The quality of the evidence was mainly low or moderate for the prespecified outcomes. The most important comparison, 'moisturizer vs. no moisturizer', showed improved Scoring Atopic Dermatitis values in the moisturizer group compared with no moisturizer [mean difference -2·42, 95% confidence interval (CI) -4·55 to -0·28], but did not meet the minimal important difference of 8·7. Fewer flares were seen (risk ratio 0·40, 95% CI 0·23-0·70) and the rate of flares was reduced (hazard ratio 3·74, 95% CI 1·86-7·50). The groups applying moisturizer used less topical corticosteroids over 6-8 weeks (mean difference -9·30 g, 95% CI 15·3 to -3·27). Glycyrrhetinic acid-, urea- and glycerol-containing creams worked better than their controls (vehicle, placebo or no moisturizer) according to both participants and physicians. More flares were reported with moisturizer alone than when combined with twice-weekly fluticasone propionate (risk ratio 2·17, 95% CI 1·55-3·11). Adding moisturizers to topical anti-inflammatory treatment was more effective than anti-inflammatory treatment alone and resulted in fewer flares.

Pediatric Contact Dermatitis Registry Data on Contact Allergy in Children With Atopic Dermatitis

Importance

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) have a dynamic relationship not yet fully understood. Investigation has been limited thus far by a paucity of data on the overlap of these disorders in pediatric patients.

Objective

To use data from the Pediatric Contact Dermatitis Registry to elucidate the associations and sensitizations among patients with concomitant AD and ACD.

Design, Setting, and Participants

This retrospective case review examined 1142 patch test cases of children younger than 18 years, who were registered between January 1, 2015, and December 31, 2015, by 84 health care providers (physicians, nurse practitioners, physician assistants) from across the United States. Data were gathered electronically from multidisciplinary providers within outpatient clinics throughout the United States on pediatric patients (ages 0-18 years).

Exposures

All participants were patch-tested to assess sensitizations to various allergens; history of AD was noted by the patch-testing providers.

Main Outcomes and Measures

Primary outcomes were sensitization rates to various patch-tested allergens.

Results

A total of 1142 patients were evaluated: 189 boys (34.2%) and 363 girls (65.8%) in the AD group and 198 boys (36.1%) and 350 girls (63.9%) in the non-AD group (data on gender identification were missing for 17 patients). Compared with those without AD, patch-tested patients with AD were 1.3 years younger (10.5 vs 11.8 years; P < .001) and had longer history of dermatitis (3.5 vs 1.8 years; P < .001). Patch-tested patients designated as Asian or African American were more likely to have concurrent AD (odds ratio [OR], 1.92; 95% CI, 1.20-3.10; P = .008; and OR, 4.09; 95% CI, 2.70-6.20; P <.001, respectively). Patients with AD with generalized distribution were the most likely to be patch tested (OR, 4.68; 95% CI, 3.50-6.30; P < .001). Patients with AD had different reaction profiles than those without AD, with increased frequency of reactions to cocamidopropyl betaine, wool alcohol, lanolin, tixocortol pivalate, and parthenolide. Patients with AD were also noted to have lower frequency of reaction to methylisothiazolinone, cobalt, and potassium dichromate.

Conclusions and Relevance

Children with AD showed significant reaction patterns to allergens notable for their use in skin care preparations. This study adds to the current understanding of AD in ACD, and the continued need to investigate the interplay between these disease processes to optimize care for pediatric patients with these conditions.

Performance and Tolerability of the Moisturizers Cetaphil® and Excipial® in Atopic Dermatitis: What is the Evidence Based on Randomized Trials?

Introduction

Moisturizers play a prominent role in the management of atopic dermatitis by improving the impaired skin barrier function and enhancing skin hydration. Their efficacy was evaluated in a recently published Cochrane Review ‘Emollients and moisturizers for eczema’.

Objective

In the present review, we summarize the performance and safety of Cetaphil^® and Excipial^® moisturizing products.

Methods

This review was carried out in compliance with standard Cochrane methodological procedures, which means independent study selection, data extraction, assessment of risk of bias, and analyses by two review authors. The quality of evidence for the predefined outcomes was rated with the GRADE approach. The prespecified outcomes of the review included participant assessments, satisfaction, adverse events, investigator assessments, prevention of flares, change in use of topical active treatment, skin barrier function and quality of life.

Results

Four randomized controlled studies examining these moisturizers were included in the previously published Cochrane Review. For the performance and tolerability of these moisturizers, there was very low to moderate quality evidence for the prespecified outcomes.

Conclusion

The results from these four studies are in line with those of the Cochrane Review that moisturizers themselves have beneficial effects, and that combining moisturizers with active topical treatment produced better results when compared to active topical treatment alone.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-017-0184-3) contains supplementary material, which is available to authorized users.

Increasing Adherence with Topical Agents for Atopic Dermatitis

Atopic dermatitis (AD) is an intensely pruritic dermatosis that develops most commonly during early infancy and childhood and may follow a chronic, relapsing course into adulthood. As a chronic disease, AD requires treatment over an extended period of time, and is therefore difficult to treat. The main difficulty stems from poor adherence to treatment by patients for reasons such as frustration with medication efficacy, inconvenience, and fear of side effects. Methods that improve adherence include creating therapeutic plans with patient preferences in mind, early follow-up visit, increasing patient education through workshops, and discussing with patients and their caretakers their fears about treatment methods. AD can be exceedingly detrimental to a patient's quality of life. Simple measures to improve adherence may improve patients' treatment outcomes and quality of life.

Emollients and moisturisers for eczema

BACKGROUND

Eczema is a chronic skin disease characterised by dry skin, intense itching, inflammatory skin lesions, and a considerable impact on quality of life. Moisturisation is an integral part of treatment, but it is unclear if moisturisers are effective.

OBJECTIVES

To assess the effects of moisturisers for eczema.

SEARCH METHODS

We searched the following databases to December 2015: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, the GREAT database. We searched five trials registers and checked references of included and excluded studies for further relevant trials.

SELECTION CRITERIA

Randomised controlled trials in people with eczema.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

We included 77 studies (6603 participants, mean age: 18.6 years, mean duration: 6.7 weeks). We assessed 36 studies as at a high risk of bias, 34 at unclear risk, and seven at low risk. Twenty-four studies assessed our primary outcome 'participant-assessed disease severity', 13 assessed 'satisfaction', and 41 assessed 'adverse events'. Secondary outcomes included investigator-assessed disease severity (addressed in 65 studies), skin barrier function (29), flare prevention (16), quality of life (10), and corticosteroid use (eight). Adverse events reporting was limited (smarting, stinging, pruritus, erythema, folliculitis).Six studies evaluated moisturiser versus no moisturiser. 'Participant-assessed disease severity' and 'satisfaction' were not assessed. Moisturiser use yielded lower SCORAD than no moisturiser (three studies, 276 participants, mean difference (MD) -2.42, 95% confidence interval (CI) -4.55 to -0.28), but the minimal important difference (MID) (8.7) was unmet. There were fewer flares with moisturisers (two studies, 87 participants, RR 0.40, 95% CI 0.23 to 0.70), time to flare was prolonged (median: 180 versus 30 days), and less topical corticosteroids were needed (two studies, 222 participants, MD -9.30 g, 95% CI -15.3 to -3.27). There was no statistically significant difference in adverse events (one study, 173 participants, risk ratio (RR) 15.34, 95% CI 0.90 to 261.64). Evidence for these outcomes was low quality.With Atopiclair (three studies), 174/232 participants experienced improvement in participant-assessed disease severity versus 27/158 allocated to vehicle (RR 4.51, 95% CI 2.19 to 9.29). Atopiclair decreased itching (four studies, 396 participants, MD -2.65, 95% CI -4.21 to -1.09) and achieved more frequent satisfaction (two studies, 248 participants, RR 2.14, 95% CI 1.58 to 2.89), fewer flares (three studies, 397 participants, RR 0.18, 95% CI 0.11 to 0.31), and lower EASI (four studies, 426 participants, MD -4.0, 95% CI -5.42 to -2.57), but MID (6.6) was unmet. The number of participants reporting adverse events was not statistically different (four studies, 430 participants, RR 1.03, 95% CI 0.79 to 1.33). Evidence for these outcomes was moderate quality.Participants reported skin improvement more frequently with urea-containing cream than placebo (one study, 129 participants, RR 1.28, 95% CI 1.06 to 1.53; low-quality evidence), with equal satisfaction between the two groups (one study, 38 participants, low-quality evidence). Urea-containing cream improved dryness (investigator-assessed) more frequently (one study, 128 participants, RR 1.40, 95% CI 1.14 to 1.71; moderate-quality evidence) with fewer flares (one study, 44 participants, RR 0.47, 95% CI 0.24 to 0.92; low-quality evidence), but more participants in this group reported adverse events (one study, 129 participants, RR 1.65, 95% CI 1.16 to 2.34; moderate-quality evidence).Three studies assessed glycerol-containing moisturiser versus vehicle or placebo. More participants in the glycerol group noticed skin improvement (one study, 134 participants, RR 1.22, 95% CI 1.01 to 1.48; moderate-quality evidence), and this group saw improved investigator-assessed SCORAD (one study, 249 participants, MD -2.20, 95% CI -3.44 to -0.96; high-quality evidence), but MID was unmet. Participant satisfaction was not addressed. The number of participants reporting adverse events was not statistically significant (two studies, 385 participants, RR 0.90, 95% CI 0.68 to 1.19; moderate-quality evidence).Four studies investigated oat-containing moisturisers versus no treatment or vehicle. No significant differences between groups were reported for participant-assessed disease severity (one study, 50 participants, RR 1.11, 95% CI 0.84 to 1.46; low-quality evidence), satisfaction (one study, 50 participants, RR 1.06, 95% CI 0.74 to 1.52; very low-quality evidence), and investigator-assessed disease severity (three studies, 272 participants, standardised mean difference (SMD) -0.23, 95% CI -0.66 to 0.21; low-quality evidence). In the oat group, there were fewer flares (one study, 43 participants, RR 0.31, 95% CI 0.12 to 0.7; low-quality evidence) and less topical corticosteroids needed (two studies, 222 participants, MD -9.30g, 95% CI 15.3 to -3.27; low-quality evidence), but more adverse events were reported (one study, 173 participants; Peto odds ratio (OR) 7.26, 95% CI 1.76 to 29.92; low-quality evidence).All moisturisers above were compared to placebo, vehicle, or no moisturiser. Participants considered moisturisers more effective in reducing eczema (five studies, 572 participants, RR 2.46, 95% CI 1.16 to 5.23; low-quality evidence) and itch (seven studies, 749 participants, SMD -1.10, 95% CI -1.83 to -0.38) than control. Participants in both treatment arms reported comparable satisfaction (three studies, 296 participants, RR 1.35, 95% CI 0.77 to 2.26; low-quality evidence). Moisturisers led to lower investigator-assessed disease severity (12 studies, 1281 participants, SMD -1.04, 95% CI -1.57 to -0.51; high-quality evidence) and fewer flares (six studies, 607 participants, RR 0.33, 95% CI 0.17 to 0.62; moderate-quality evidence), but there was no difference in adverse events (10 studies, 1275 participants, RR 1.03, 95% CI 0.82 to 1.30; moderate-quality evidence).Topical active treatment combined with moisturiser was more effective than active treatment alone in reducing investigator-assessed disease severity (three studies, 192 participants, SMD -0.87, 95% CI -1.17 to -0.57; moderate-quality evidence) and flares (one study, 105 participants, RR 0.43, 95% CI 0.20 to 0.93), and was preferred by participants (both low-quality evidence). There was no statistically significant difference in number of adverse events (one study, 125 participants, RR 0.39, 95% CI 0.13 to 1.19; very low-quality evidence). Participant-assessed disease severity was not addressed.

AUTHORS' CONCLUSIONS

Most moisturisers showed some beneficial effects, producing better results when used with active treatment, prolonging time to flare, and reducing the number of flares and amount of topical corticosteroids needed to achieve similar reductions in eczema severity. We did not find reliable evidence that one moisturiser is better than another.