Allergen avoidance and prevention of atopy

Potential Allergenicity of Plants Used in Allergological Communication: An Untapped Tool for Prevention

Plants are often used to illustrate allergy-related medical products, services, patient information materials and news. The illustration of allergenic plants is an important tool in patient education, contributing to the prevention of pollinosis, as patients can recognize plants and avoid pollen exposure. In this study, it is aimed to evaluate the pictorial content of allergy-related websites depicting plants. A total of 562 different photographs depicting plants were collected using image search, identified and categorized according to their potential allergenicity. Of the total 124 plant taxa, 25% of plants were identified to the genus level and a further 68% were identified to the species level. Plants with low allergenicity were found in 85.4% of the pictures, while plants of high allergenicity were shown in only 4.5% of the pictorial information. Brassica napus was the most frequent species identified (8.9% of the overall identified plants), while blooming Prunoidae, Chrysanthemum spp. and Taraxacum officinale were also common. Considering both allergological and design aspects, some plant species have been proposed for more professional and responsible advertising. The internet has the potential to provide visual support for patient education in allergenic plants, but emphasis must be put on the transmission of the correct visual message.

Epicutaneous sensitization to food allergens in atopic dermatitis: What do we know?

Atopic dermatitis (AD) is a chronic inflammatory skin disease mainly affecting children, which has no definitive curative therapy apart from natural outgrowing. AD is persistent in 30%-40% of children. Epithelial barrier dysfunction in AD is a significant risk factor for the development of epicutaneous food sensitization, food allergy, and other allergic disorders. There is evidence that prophylactic emollient applications from birth may be useful for primary prevention of AD, but biomarkers are needed to guide cost-effective targeted therapy for high-risk individuals. In established early-onset AD, secondary preventive strategies are needed to attenuate progression to other allergic disorders such as food allergy, asthma, and allergic rhinitis (the atopic march). This review aims to describe the mechanisms underpinning the development of epicutaneous sensitization to food allergens and progression to clinical food allergy; summarize current evidence for interventions to halt the progression from AD to food sensitization and clinical food allergy; and highlight unmet needs and directions for future research.

Dust mite avoidance for the primary prevention of atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

Dust mite sensitization plays a controversial role in the development of atopic dermatitis. Despite a lack of evidence for its efficacy, dust mite avoidance is commonly recommended for the prevention and treatment of atopic dermatitis. We aimed to evaluate whether dust mite avoidance strategies reduce the risk of developing atopic dermatitis in high-risk infants compared to randomized controls.

METHODS

Studies were obtained by searching MEDLINE, PubMed, Scopus, The Cochrane Library, and The Global Resource of Eczema Trials databases. We included randomized, controlled trials of high-risk infants treated with a dust mite avoidance intervention and assessed for atopic dermatitis. Data were extracted independently by two reviewers using predefined criteria.

RESULTS

Seven randomized controlled trials met our inclusion criteria (total n = 3040). Studies were largely unblinded but otherwise of reasonable quality. Three trials utilizing a dust mite avoidance approach but not additional interventions were combined in a meta-analysis. Dust mite avoidance provided no benefit in the prevention of atopic dermatitis (relative risk (RR) = 1.08, 95% confidence interval (CI) = 0.78-1.49, I(2) = 73%).

CONCLUSIONS

Dust mite avoidance strategies alone or in combination with additional allergen avoidance modalities do not decrease the risk of developing atopic dermatitis and, given the current state of the evidence, should not be recommended for this purpose. The utility of dust mite avoidance for the treatment of atopic dermatitis or for the prevention and treatment of asthma or seasonal rhinoconjunctivitis are outside the scope of this review.

Diet for the prevention of asthma and allergies in early childhood: much ado about something?

In the last decades there has been an increase in allergic disease throughout the world, particularly in children. Attempts have been made to identify the causes of this "allergy epidemic" in environmental changes and changes in population hygiene, lifestyle, socioeconomic level, and eating habits that would exert epigenetic effects. Dietetic hypotheses have been mainly focussed in long-chain polyunsaturated fatty acids, vitamin D, antioxidants, Mediterranean diet, and fruits, vegetables and fish consumption. Although the data suggest a certain association between diet and the development of asthma/allergy, there is no evidence that diet has an impact upon the prevalence of such diseases after early infancy. If indeed there is such an impact, it is likely to be confined to the prenatal period and the first months of life - when it is still possible to modulate the development of the respiratory, digestive and immune systems. Thus, once the most appropriate preventive measures have been defined, these should be implemented during pregnancy and lactation. The existing scientific evidence is unable to recommend any primary preventive measure in the general population or in different population subgroups. Special or restrictive diets in pregnant or nursing women are not indicated. Exclusive breastfeeding for six months is questioned, since solid foods should begin to be introduced at around four months of age. Once the atopic process has started, no nutritional strategies have been found to be effective as secondary or tertiary preventive measures. Longitudinal studies in cohorts of pregnant women or newborn infants could help clarify these issues.

Association between indoor mold and asthma among children in Buffalo, New York

Asthma is a leading chronic disease among children and places a significant burden on public health. Exposure to indoor mold has been associated with asthma symptoms. However, many mold assessments have relied on visual or other identification of damp conditions and mold presence, thus have not examined associations with specific fungal genera. The objective of this case-control study was to examine the relationship between airborne mold concentrations and asthma status among children and to identify the contribution from specific mold genera in air. Participants completed a questionnaire of home environmental conditions and underwent indoor air sampling in the home, from which viable and total-count fungal spores were quantified. The most prevalent fungi in the homes were the allergenic molds Cladosporium (98% and 87% of homes from viable and total count samples, respectively) and Penicillium (91% and 73%). There were no significant differences in mean fungal concentrations between the homes of cases and controls, although the observed rate of exposure to several molds was higher among the cases. Among children who lacked a family history of asthma, cases had significantly higher exposures to viable Aspergillus. Measured humidity levels in the home corresponded with some self-reported indicators of mold and dampness.

PRACTICAL IMPLICATIONS

The results of this study support existing literature that indoor fungal exposures play a role in current asthma status and that some qualitative assessments of mold exposure correspond to fungi present in indoor air.

High prevalence of skin test positivity in severe or difficult-to-treat asthma

BACKGROUND

Skin tests are considered the gold standard for detecting allergen-specific immunoglobulin E (IgE) in the clinical setting and are an important tool for diagnosing and managing allergic asthma.

OBJECTIVE

To assess the prevalence of skin testing in patients > or = 12 years enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study.

METHODS

Patients were asked whether they had ever been skin tested and, if so, they were asked to provide the test results. Clinical characteristics were used to compare positive (ST+), negative (ST-), and skin test not done (STND) patients.

RESULTS

Of 2,985 patients eligible, 85.8% recalled being skin tested. Of those tested, 93.5% were positive (allergist 95.7%, pulmonologist 87.3%). A high proportion of Whites (93.5%) and non-Whites (94.0%) were ST+; however, more non-Whites had never been skin tested (21.7% vs. 12.3%, respectively; p < 0.0001). Total serum IgE was 104.6 IU/mL for ST+ patients, 87.1 IU/mL for STND patients, and 32.4 IU/mL for ST- patients. Age at asthma onset, duration of asthma, and the prevalence of atopic disorders and asthma triggers differentiated the ST+ from the ST- group. Disease severity appeared similar between the two groups. In general, values for STND patients were closer to the ST+ group, suggesting that those not tested would have been ST+ if administered a test.

CONCLUSIONS

The prevalence of ST+ patients was high in allergy and pulmonology practices, and in White and non-White patients. These data support the utility of a more complete allergic evaluation in severe asthmatics. Skin testing appears associated with disease pathophysiologies in asthma.

Viewpoint: are doctors responsible for the increase in allergic diseases?

There is no exact explanation for the increase in allergic diseases that occurred since the last two decades. An increased allergen exposure and/or a decreased bacterial load cannot explain the phenomenon completely. Other causal factors that rose at the beginning of the 1980s must be taken into consideration. Important changes at that time in our management of children were the worldwide switch from aspirin to paracetamol, the introduction of broad-spectrum antibiotics such as cephalosporins and the advice to avoid dust and pets in newborns from allergic families. General application of these new approaches, in itself or in combination, might be responsible, at least in part, for the increase of allergic diseases in children.

Indoor air quality and human health: truth vs mass hysteria

Indoor air quality is an important issue, because anything we breathe can potentially affect our health. To determine if there is a real health risk, well-designed scientifically valid studies must be performed. Although much attention has focused on sick building syndrome, chemical sensitivities, and mycotoxicosis, there actually is very little evidence that these conditions have an adverse effect on human health. In contrast, real health issues have been shown to exist regarding indoor air triggers of allergies and asthma. Outdoor allergens are difficult to avoid because the pollen grains we encounter outdoors, which are the size that can cause allergies, are windborne and can travel for miles. However, indoor allergens can cause severe allergic symptoms and may also have a priming effect on an individual’s susceptibility to simultaneous or subsequent exposure of other outdoor allergens. Therefore, it is important to minimize exposure to indoor allergens. Determination of individual susceptibility can be paired with knowledge of the patient’s indoor exposure pattern to produce a customized management plan of avoidance, which can be used in conjunction with pharmacological treatment of allergies and asthma, as well as immunotherapy.