Pre-natal and post-natal exposure to respiratory infection and atopic diseases development: a historical cohort study

The Role of the Environmental Risk Factors in the Pathogenesis and Clinical Outcome of Atopic Dermatitis

Atopic dermatitis (AD) prevalence is rising worldwide. Literature data suggest the incidence of AD in developing countries is gradually getting close to that of developed ones, in which AD affects 20% of the paediatric population. Such an increment, associated with significant variations in prevalence among the various countries, underlines the importance of environmental factors in the disease onset. Among these, great importance is given to hygiene, intestinal microbiota, exposure to bacterial endotoxins, outdoor living with contact to animals, atmospheric pollution, weather, and diet. Genetic (alteration of the skin barrier function) as well as immunologic factors concur with the environmental ones. Only the systematical study of all these elements can best elucidate AD epidemiology.

Topical Coconut Oil in Very Preterm Infants: An Open-Label Randomised Controlled Trial

BACKGROUND

The immature fragile skin of preterm infants represents an inadequate protective barrier. The emollient and anti-infective properties of coconut oil make it a potentially beneficial topical agent for this population.

OBJECTIVES

Our aim was to evaluate feasibility, safety, and the effects of topical coconut oil on skin condition in very preterm infants.

METHODS

An open-label randomised controlled trial in preterm infants <30 weeks' gestation was conducted. Enrolled infants were randomised to receive either routine care or topical coconut oil (5 mL/kg) twice daily for 21 days, starting within 24 h of birth. The neonatal skin condition was the primary outcome, and was assessed using the Neonatal Skin Condition Score (NSCS) on days 1, 7, 14, and 21. The number of coconut oil applications was recorded to assess clinical feasibility and all enrolled infants were monitored for adverse effects of topical coconut application, such as skin irritation.

RESULTS

A total of 72 infants born <30 weeks' gestation were enrolled (36 infants per arm), with comparable demographic characteristics. Topical application of coconut oil was feasible and without adverse effects. The NSCS was maintained in the coconut oil group throughout the intervention period, but deteriorated from a median (IQR) of 3 (3-4) on day 1 to 4 (4-4) on day 21 in the control group (p = 0.01). There were no differences in common neonatal outcomes, including sepsis, necrotising enterocolitis, retinopathy of prematurity, chronic lung disease, and mortality.

CONCLUSIONS

Topical coconut oil maintained a better skin condition in very preterm infants without adverse effects. This simple, safe, and affordable intervention warrants further investigation.

Prevalence of and risk factors for atopic dermatitis: A birth cohort study of infants in southeast Turkey

BACKGROUND

Atopic dermatitis (AD) is most common in the first year of life. The aim of this study was to determine the prevalence of and risk factors for AD in a birth cohort of infants from southeast Turkey.

METHODS

Adana Paediatric Allergy Research (ADAPAR) birth cohort study was derived from 1377 infants who were born in Cukurova University, Medical Hospital, Adana, Turkey between February 2010 and February 2011. At birth, a physical examination was performed, cord blood samples were taken, and the mother completed a baseline questionnaire that provided data on gestational conditions, family history of allergic diseases and environmental exposures. Follow-up visits scheduled at 3, 6, and 12 months included an infant physical examination and an extended questionnaire. Skin prick test was performed and food-specific IgE levels were measured at 6 and 12 months. Atopic dermatitis was diagnosed based on confirmatory examination by a physician.

RESULTS

Of the 1377 infants enrolled, 59 (4.3%) were diagnosed with AD as of 12 months. Maternal allergic disease (ORs 6.28, 95% CI 1.03-38.30; p=0.046), maternal infection during gestation (ORs 3.73, 95% CI 1.25-11.09; p=0.018), and presence of food allergy (ORs 13.7, 95% CI 3.07-61.0; p=0.001) were identified as risk factors for AD. Breastfeeding and cord blood IgE levels were not identified as risk factors.

CONCLUSIONS

In this cohort we found prevalence of AD as 4.3% during the first year of life. Positive family history of atopic diseases, prenatal infections and presence of food allergy are the risk factors for early presentation of AD.

Can atopic dermatitis be prevented?

Atopic dermatitis has become a health problem in our setting due to its rising prevalence, impact on quality of life, associated costs, and role in the progression to other atopic diseases. Furthermore, atopic dermatitis has no definitive cure and therefore preventive measures are important. In this article, we review the latest advances in both primary prevention (reduction of the incidence of atopic dermatitis) and secondary prevention (reduction of associated morbidity and reduction of the atopic march). We analyze the different preventive strategies available, including modification of the immune system through microbial exposure, induction of immune tolerance through antigen exposure, and restoration of skin barrier function to halt the atopic march. Dermatologists need to be familiar with these strategies in order to apply them where necessary and to accurately inform patients and their relatives to prevent misguided or inappropriate actions.

New insights into the epidemiology of childhood atopic dermatitis

There is a growing desire to explain the worldwide rise in the prevalence of atopic dermatitis (AD). Trend data on the burden of AD suggest that the picture in the developing world may soon resemble that of wealthier nations, where AD affects over 20% of children. This, combined with significant variations in prevalence within countries, emphasizes the importance of environmental factors. Many hypotheses have been explored, from the modulation of immune priming by hygiene, gut microbiota diversity, and exposure to endotoxins through farm animals to the effects of pollution, climate, and diet. The discovery of the filaggrin skin barrier gene and its importance in AD development and severity has brought the focus on gene-environment interactions and the identification of environmental factors that impact on skin barrier function. This article reviews our current understanding of the epidemiology of AD, with an emphasis on the findings reported in the international literature over the last 5 years.

Management of patients with atopic dermatitis: the role of emollient therapy

Atopic dermatitis is a common inflammatory skin disorder that afflicts a growing number of young children. Genetic, immune, and environmental factors interact in a complex fashion to contribute to disease expression. The compromised stratum corneum found in atopic dermatitis leads to skin barrier dysfunction, which results in aggravation of symptoms by aeroallergens, microbes, and other insults. Infants—whose immune system and epidermal barrier are still developing—display a higher frequency of atopic dermatitis. Management of patients with atopic dermatitis includes maintaining optimal skin care, avoiding allergic triggers, and routinely using emollients to maintain a hydrated stratum corneum and to improve barrier function. Flares of atopic dermatitis are often managed with courses of topical corticosteroids or calcineurin inhibitors. This paper discusses the role of emollients in the management of atopic dermatitis, with particular emphasis on infants and young children.

Association of cord blood cytokine levels with wheezy infants in the first year of life

As antenatal environment may influence the development of atopy-predisposing immune response, cord blood cytokine productions may be an important predictor for wheezing. We investigated cord blood cytokines in a prospective birth cohort, intensively monitored for wheezy infant outcome at 1 yr. Cord blood serum samples from 269 children were assayed for interleukin (IL)-1beta, -2, -4 to -8, -10, -12 (p70), -13, and -17, interferon-gamma, tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor (G-CSF), monocyte chemotactic protein-1, and macrophage inflammatory protein-1beta. Associations between family histories, antenatal and perinatal factors, cord blood cytokine concentrations, and wheezy infant outcomes (wheezing more than two times) were analyzed. In cord blood sera from 269 children, there were associations between high levels of IL-6, -8 and G-CSF concentrations, and cesarean section. Data at 1 yr were obtained from 213 infants, including 33 wheezy infants. Risk of wheezing was related to gestational age, birth weight, cesarean section, and maternal eczema, but not to bacterial/viral infection during pregnancy, maternal asthma, maternal smoking, or paternal history. High level of cord blood IL-8 concentration had a significant association with wheezy infant outcomes at 1 yr (p = 0.025). By using multivariate logistic regression analysis, birth weight [odds ratio(OR) = 0.998, 95% confidence interval (CI) = 0.997-1.000] and maternal eczema (OR = 5.356, 95% CI = 1.340-21.41), but no other factors, were significant predictors of wheezy infants. Birth weight, gestational age, and maternal history were important risk factors for wheezing in the first year of life. Several cord blood cytokine productions were influenced by cesarean section, and IL-8 may be a predictor for recurrent wheezing at 1 yr.

Update on allergies in pregnancy, lactation, and early childhood

The factors responsible for the induction of allergic disease at an early age have not been completely identified. Therefore a major research focus is their identification to elaborate recommendations for prevention of sensitization in high-risk or atopic children. This review analyzes known or suspected reasons for sensitization in pregnant women and infants from both clinical and experimental animal studies. Recent studies and meta-analyses could not confirm the protective effect of an allergen-poor diet on the part of the mother during pregnancy and lactation. Likewise, the type of bottle feeding or the introduction of solid food into the child's diet might not significantly influence the development of atopy, allergy, or asthma in the child's life. Disappointingly, the few preventive measures remaining to reduce the risk of allergic sensitization and atopic diseases in mother and child are the avoidance of smoking and alcohol consumption during pregnancy and lactation and the avoidance of the impairment of gastric function. Further studies are urgently needed to address the influence of certain foods and nutrients, as well as environmental factors, for prevention of allergic diseases in the low- or high-risk infant.

Hygiene, microbial diversity and immune regulation

PURPOSE OF REVIEW

Sanitation, antibiotics and vaccines have done more to extend life expectancy than any other medical innovation. Concern exists, however, about the link between hygiene and increased incidence of immune-mediated disorders.

RECENT FINDINGS

Studies confirm higher prevalence of asthma and allergic diseases in urban areas and developed countries rather than rural areas and developing countries. There is an inverse association between family size and disease. The debate over whether infection precipitates or prevents immune dysregulation remains a contentious one. Our knowledge about the microbial composition of the intestinal ecosystem is expanding rapidly with the introduction of molecular techniques. Differences in gut bacteria between health and atopy or inflammatory bowel disease are repeatedly reported. Recent data in inflammatory bowel disease suggest reduced species diversity and temporal instability of the gut microecosystem. The gut is a major site for induction of regulatory T cells, which secrete immunosuppressive cytokines. Not only infections, but also some commensals induce regulatory pathways, which seem to be functionally deficient in multiple sclerosis, allergies and inflammatory bowel disease.

SUMMARY

Changes in lifestyle leading to decreased exposure to certain nonpathogenic species that are important for the development of immunoregulatory mechanisms are probably associated with increased incidence of some immune-mediated diseases, such as allergies and inflammatory bowel disease.