Atopic Dermatitis: Disease Background and Risk Factors.

Multiple risk factors have been associated with the development of atopic dermatitis (AD). Recent advances in understanding the role of genetics in this disease have been made, with discovery of the filaggrin (FLG) gene as the most notable so far. In addition to FLG gene mutations as a risk factor for AD, a positive family history of atopic or allergic disease in either parent has been shown to confer a greater risk of developing AD. Atopic dermatitis usually presents early in life and is thought to represent the initial step in the "atopic march," which is characterized by the development of other atopic diseases later in life such as asthma, allergic rhinitis, and/or rhinoconjunctivitis, food allergies, and hay fever. Other comorbid diseases that have been associated with AD include increase risk of viral and bacterial skin infections, neuropsychiatric diseases such as attention-deficit hyperactivity disorders (ADHD), and autistic spectrum disorder (ASD). Patients with AD have also been found to have worse sleep quality overall compared to patients without AD. In this chapter, we will discuss the risk factors associated with development of atopic dermatitis as well as the most commonly reported comorbidities in patients with this disease.

Association between fine mapping thymic stromal lymphopoietin and atopic dermatitis onset and persistence.

BACKGROUND: Atopic dermatitis (AD) is a common chronic relapsing skin disease. Genetic variants have been associated with skin barrier function and immune regulation. Thymic stromal lymphopoietin (TSLP), an immune regulator, has been previously associated with AD. OBJECTIVE: To fine map TSLP and evaluate associations with the onset and persistence of AD. METHODS: TSLP variation was determined using targeted massively parallel sequencing in a longitudinal cohort of children with AD. Evaluations included linkage disequilibrium and the persistence of AD for as many as 10 years of follow-up. The association between the presence of AD and rs1898671 variation was evaluated in a second independent cohort. RESULTS: The minor variant frequency for rs1898671 was 23.5% (95% CI, 21.4%-25.8%). This variant was not in linkage disequilibrium with other TSLP variants in the longitudinal cohort (n = 741). White children with AD were less likely to have rs1898671 variant (odds ratio [OR], 1.41; 95% CI, 1.20-1.66) than Genome Aggregation Database controls. Children with AD and the rs1898671 variant during follow-up were more likely to have remission than children who were wild type for rs1898671 (OR, 1.56; 95% CI, 1.26-1.91). In the second cohort (n = 585), the rs1898671 variant was less prevalent in those with AD than those without. The protective effect was greater in rs1898671 heterozygotes (OR, 1.91; 95% CI, 1.34-2.75) than homozygotes (OR, 1.28; 95% CI, 0.61-2.70). CONCLUSION: TSLP and specifically rs1898671 are important in the pathogenesis of AD and could represent a potential clinical target for the development of therapies to treat individuals with AD.

Health Utility Scores of Atopic Dermatitis in US Adults.

BACKGROUND: The impact of atopic dermatitis (AD) on health-related quality of life and health utility in the US adult population is not well established. OBJECTIVE: To determine the health utilities and quality-adjusted life-years (QALYs) lost in adults with AD versus without AD in the US population. METHODS: A cross-sectional, population-based study of 3495 adults was performed. AD was determined using modified UK diagnostic criteria for AD. AD severity was assessed using self-reported global AD severity, the Patient-Oriented Eczema Measure, the Patient-Oriented Scoring AD, and the Patient-Oriented Scoring AD itch and sleep. Six-dimensional health state short form (SF-6D) health utility scores and total QALY loss were assessed. RESULTS: The mean SF-6D score was lower in adults with AD compared with healthy adults (0.69 [95% CI, 0.68-0.70] versus 0.79 [95% CI, 0.77-0.79]). In particular, those with moderate-to-severe AD (mean, 0.53-0.66) had similar or lower SF-6D scores compared with those with all other self-reported disorders examined, except autoimmune disorders. Adults with AD and atopic comorbidities had significantly lower SF-6D scores compared with those without atopic comorbidities. Among the 7 disorders examined, AD was associated with higher total QALY loss than autoimmune disorders, diabetes, food allergy, and heart disease in both males and females. The largest QALY loss was for moderate AD in females and mild AD in males. CONCLUSIONS: Moderate-to-severe AD is associated with significant decrements of health utility in the US population. These data illustrate the heavy societal burden of moderate and severe AD and provide important insight for prioritization of resource allocation and cost-effectiveness research.

Effect of 2 Psoriasis Treatments on Vascular Inflammation and Novel Inflammatory Cardiovascular Biomarkers: A Randomized Placebo-Controlled Trial.

BACKGROUND: Psoriasis is a chronic inflammatory disease associated with dyslipidemia, cardiovascular events, and mortality. We aimed to assess and compare the effect of treatment of moderate-to-severe psoriasis with adalimumab or phototherapy on vascular inflammation and cardiovascular biomarkers. METHODS AND RESULTS: Randomized, double-blind, trial of adalimumab, phototherapy, and placebo (1:1:1) for 12 weeks, with crossover to adalimumab for 52 weeks total. Outcomes included vascular inflammation by 18F-fluorodeoxyglucose positron emission tomography/computed tomography and biomarkers of inflammation, insulin resistance, and lipoproteins. Ninety-seven patients were randomized, 92 completed the randomized controlled trial portion; 81 entered the adalimumab extension with 61 completing 52 weeks of adalimumab. There was no difference in change in vascular inflammation at week 12 in the adalimumab group (change compared with placebo, 0.64%; 95% confidence interval, -5.84% to 7.12%) or the phototherapy group (-1.60%; 95% confidence interval, -6.78% to 3.59%) or after 52-week adalimumab treatment (0.02% compared with initiation; 95% confidence interval, -2.85% to 2.90%). Both adalimumab and phototherapy decreased inflammation by serum CRP, interleukin-6. Only adalimumab reduced tumor necrosis factor and glycoprotein acetylation at 12 and 52 weeks. Neither had an impact on metabolic markers (insulin, adiponectin, and leptin). Only phototherapy increased high-density lipoprotein-p at 12 weeks. At 52-week of adalimumab cholesterol efflux and high-density lipoprotein-p were reduced. CONCLUSIONS: Adalimumab reduced key markers of inflammation including glycoprotein acetylation compared with phototherapy with no effect on glucose metabolism and vascular inflammation, and potential adverse effects on high-density lipoprotein. Glycoprotein acetylation improvement may partially explain the beneficial effects of adalimumab seen in observational studies. Larger studies with more detailed phenotyping of vascular disease should assess the comparative differences in the effects of adalimumab and phototherapy seen in our study. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01866592 and NCT01553058.

Uncommon Filaggrin Variants Are Associated with Persistent Atopic Dermatitis in African Americans.

Atopic dermatitis (AD) is a common illness that has been associated with filaggrin gene (FLG) loss of function (LoF) variation. In African Americans, a group that commonly has AD and has not been well studied, FLG LoF variation is rarely found. Our objective was to use massively parallel sequencing to evaluate FLG LoF variation in children of African ancestry to evaluate the association between FLG LoF variation and AD and AD persistence. We studied 262 African American children with AD. Nine unique FLG exon 3 LoF variants were identified for an overall minor variant frequency of 6.30% (95% confidence interval [CI] = 4.37-8.73). The most common variants were p.R501X (1.72%, 95% CI = 0.79-3.24), p.S3316X (1.34%, 95% CI = 0.54-2.73), and p.R826X (0.95%, 95% CI = 0.31-2.2). Over an average follow-up period of 96.4 (95% CI = 92.0-100.8) months, African American children with FLG LoF were less likely to be symptom free (odds ratio = 0.36, 95% CI = 0.14-0.89, P = 0.027) compared with a FLG wild-type child. In contrast to previous reports, uncommon FLG LoF variants in African American children exist and are associated with AD and more persistent AD. In contrast to Europeans, no FLG LoF variants predominate in African American children. Properly determining FLG LoF status requires advanced sequencing techniques.