Maternal experiences of peanut avoidance during pregnancy/lactation: an in-depth qualitative study

The combination of Ara h 2-sIgE and basophil activation test could be an alternative to oral food challenge in cases of suspected peanut allergy

BACKGROUND

Most children with peanut sensitisation do not have a clinical peanut allergy (PA). Oral food challenge (OFC) is then necessary to diagnose PA and assess the reactive dose of the allergen. However, OFC is laborious to perform, expensive and stressful. We evaluated whether in vitro tests, such as basophil activation test (BAT), allergen-specific IgE (sIgE) and their combination, could be used to replace OFC for the diagnosis of PA in children.

METHODS

Ninety-one patients aged 6 months to 18 years with suspected PA were prospectively recruited. These patients then underwent an OFC to assess PA. Whole peanut-sIgE, Ara h 2-sIgE, Ara h 8-sIgE and %CD63+ basophils (CCR3+ /SCClow ) to peanut measured by BAT were investigated for PA diagnosis.

RESULTS

Forty-one patients had a positive peanut OFC, and the remaining 50 were only sensitised. All patients with Ara h 2-sIgE >7 kUA /L were allergic to peanut. A threshold of 6% for activated basophils yielded a sensitivity of 95% and a specificity of 54%. All patients with Ara h 2-sIgE ≤7 kUA /L and BAT ≤6% (n = 22) had a negative OFC except for one who presented an oral syndrome due to PR-10 sensitisation.

CONCLUSIONS

We have shown that Ara h 2-sIgE >7 kUA/L is a discriminating threshold for the diagnosis of PA. Furthermore, when Ara h 2-sIgE ≤7 kUA/L and BAT ≤6%, patients do not need to adjust their diet and, thus, do not need an OFC.

Practical Challenges and Considerations for Early Introduction of Potential Food Allergens for Prevention of Food Allergy

Recent randomized controlled trials aimed at the prevention of food allergy have led to sweeping changes in food allergy prevention guidelines. Emphasis is now on the introduction of potential food allergens, particularly peanut and egg, rather than avoidance. Although guidelines recommend against delaying the introduction of other potential allergens, there remains little or no evidence of the benefit of their early introduction. Parents and physicians alike report a need for greater guidance and resources on early potential allergen introduction in the complementary feeding period. A thorough understanding of early introduction literature, current prevention guidelines, and infant nutrition will empower physicians to address patient needs and concerns both when advice is established as effective and where uncertainty remains. We discuss the state of the science, compare recommendations between guidelines, and provide practical options to introduce allergenic foods, alongside other complementary foods, within the first year of life. We include a review of the available literature, including review and suggestions of potential doses of food allergens, and the first published comparison of commercially available products and homemade early introduction foods to help clinicians support their patients. We address the nutritional, dietary, and practical considerations of introducing food allergens in the first year of life while adhering to infant feeding guidelines. Finally, given the limitations of existing guidelines, we review the need for shared decision-making between physicians and parents regarding early allergen introduction.

Pros and cons of pre-emptive screening programmes before peanut introduction in infancy

Peanut allergy is an important public health concern and causes substantial psychosocial comorbidity. Although fatal anaphylaxis is rare (occurring at 0·03-0·3 per million person-years in the general population), peanuts are one of the most frequent causes of food allergy mortality. The Learning Early About Peanut study transformed prevention of peanut allergy by showing that early introduction of peanut into the diet of children at high risk (ie, those with an egg allergy or severe eczema) reduced the relative risk of peanut allergy at age 5 years by 81%. Following publication of this study, the US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, convened an expert panel, which recommended that, for infants with severe eczema or egg allergy, health professionals should strongly consider evaluation with peanut-specific serological IgE or skin prick test (or both) and, if necessary, an oral food challenge before peanut introduction. In the USA, depending on test results, peanut-containing foods are recommended to be introduced from age 4-6 months in infants with severe eczema or egg allergy. Early introduction to peanuts is also advocated for children with either mild to moderate or no eczema, and in children who are not allergic to egg, but without screening before peanut introduction. However, the NIAID addendum guidelines contrast with other international approaches that do not advocate for allergy screening at a population level before introducing peanuts into infants' diets. In this Review, we evaluate the advantages and disadvantages of a pre-emptive screening approach before the early introduction of peanuts in infants at high risk of peanut allergy.

Peanut allergy diagnosis: Moving from basic to more elegant testing

Peanut allergy (PNA) is an IgE-mediated immune disorder, which merits particular attention due to its impact on the health and quality of life of millions of patients worldwide. PNA tends to develop in early life and resolves in only 20% of peanut-allergic children. It accounts for the majority of severe food-related allergic reactions. An accurate diagnosis of PNA is vital. In this review, we present the approach to the diagnosis of peanut allergy, starting from the history and proceeding to measures of overall sensitization and then to component-resolved diagnostics and oral food challenges as indicated. Additional testing in development includes basophil activation testing and determination of epitopes for peanut-allergic responses. Based on the literature, stepwise approaches and predictive models for diagnosing PNA are also presented.

Developing a food allergy curriculum for parents

BACKGROUND

Food allergy (FA) is potentially severe and requires intensive education to master allergen avoidance and emergency care. There is evidence suggesting the need for a comprehensive curriculum for food allergic families.

METHODS

This paper describes the results of focus groups conducted to guide the development of a curriculum for parents of food allergic children. The focus groups were conducted using standard methodology with experienced parents of food allergic children.

RESULTS

Participants were parents (n = 36) with experience managing FA recruited from allergy clinics at two academic centers. Topics identified by parents as key for successful management included as expected: (i) early signs/symptoms, (ii) 'cross-contamination', (iii) label-reading, (iv) self-injectable epinephrine; and (v) becoming a teacher and advocate. Participants also recommended developing a 'one page-road map' to the information, and to provide the information early and be timed according to developmental stages/needs. Suggested first points for curriculum dissemination were emergency rooms, obstetrician and pediatrician offices. Participants also recommended targeting pediatricians, emergency physicians, school personnel, and the community-at-large in educational efforts. Parents often sought FA information from non-medical sources such as the Internet and support groups. These resources were also accessed to find ways to cope with stress. Paradoxically, difficulties gaining access to resources and uncertainty regarding reliability of the information added to the stress experience.

DISCUSSION

Based on reports from experienced parents of food allergic children, newly diagnosed parents could benefit from a comprehensive FA management curriculum. Improving access to clear and concise educational materials would likely reduce stress/anxiety and improve quality of life.

Teenagers' experiences of living with food hypersensitivity: a qualitative study

Teenagers are a high-risk group for food-hypersensitivity fatalities, engage in risk-taking behaviours and may experience impaired quality of life. Understanding their experience is important to inform their care. This study aimed to describe the lived experiences of teenagers with food hypersensitivity. Individual semi-structured interviews were conducted with 21 teenagers (13-18 yr) with food hypersensitivity to a variety of foods and analysed using a phenomenological approach. Teenagers described living with (or coming to know) food hypersensitivity (FHS) as a way of life but still found living with food hypersensitivity to be burdensome. A necessary part of living with food hypersensitivity was coping with associated burden; a variety of coping strategies were employed to this effect. Teenagers described ways in which the burden of living with food hypersensitivity was alleviated or exacerbated by others. Management of food hypersensitivity was based on an assessment of acceptable risk resulting in varying levels of precaution taking. Teenagers' understanding of their FHS and ability to cope with it needs to be regularly assessed. Educational support may be required to ensure they take an appropriate level of precautions to minimize the chance of future reactions while not over compromising their quality of life. Psychological support may be required to help them to utilize healthy adaptive strategies to cope with the stresses of living with FHS. This approach is also likely to facilitate the smooth handover of responsibility from parent to teenager.

Factors associated with maternal dietary intake, feeding and weaning practices, and the development of food hypersensitivity in the infant

Maternal diet during pregnancy and breastfeeding, as well as infant feeding and weaning practices, may play a role in the development of sensitization to food and food hypersensitivity (FHS) and need further investigation. Pregnant women were recruited at 12 wk pregnancy. Information regarding family history of allergy was obtained by means of a questionnaire. A food frequency questionnaire was completed at 36 wk gestation. Information regarding feeding practices and reported symptoms of atopy was obtained during the infants' first 3 yr of life. Children were also skin-prick tested at 1, 2 and 3 yr to a pre-defined panel of food allergens. Food challenges were conducted where possible. Maternal dietary intake during pregnancy, and breast-feeding duration did not influence the development of sensitization to food allergens or FHS, but weaning age (>or=16 wk) did for sensitization at 1 yr (p = 0.03), FHS by 1 yr (p = 0.02), sensitization at 3 yr (p = 0.01) and FHS by 3 yr (p = 0.02). In contrast, children who were not exposed to a certain food allergen before the age of 3-6 months were less likely to become sensitized or develop FHS. Women with a family history of allergic disease were more likely to breastfeed exclusively at 3 months (p = 0.008) and avoid peanuts from the infant's diet at 6 months (p = 0.03). Maternal dietary intake during pregnancy, and breast-feeding duration did not appear to influence the development of sensitization to food allergens or FHS. Weaning age may affect sensitization to foods and development of FHS. A history of allergic disease has very little impact on maternal dietary, feeding, and weaning practices.

A EuroPrevall review of factors affecting incidence of peanut allergy: priorities for research and policy

Peanuts are extensively cultivated around the world, providing a foodstuff that is both cheap to produce and nutritious. However, allergy to peanuts is of growing global concern, particularly given the severity of peanut-allergic reactions, which can include anaphylaxis and death. Consequently, it is important to understand the factors related to the prevalence of peanut allergy in order to inform efforts to ameliorate or pre-empt the condition. In this article we review evidence for the relevance of factors hypothesized to have some association with allergy prevalence, including both genetic and environmental factors. Although our analysis does indicate some empirical support for the importance of a number of factors, the key finding is that there are significant data gaps in the literature that undermine our ability to provide firm conclusions. We highlight these gaps, indicating questions that need to be addressed by future research.

Ready-to-use introduction schedules for first exposure to allergenic foods in children at home

BACKGROUND

The vast majority of children will undergo their first exposure to common allergenic foods at home. However, the first exposure may lead to clinical reactions. It has been proposed to introduce allergenic foods gradually into the diets of children at risk for food allergy, but no practical dietary advice has been devised.

OBJECTIVE

The aim of this study was to devise safe introduction schedules for common allergenic foods for use at home, based on the challenge doses as administered in double-blind, placebo-controlled food challenge (DBPCFCs) in children who were never exposed previously to these foods.

METHODS

Seventy-two DBPCFCs were performed in 63 children as a first known exposure. The incrementing challenge doses were converted into equivalent portions of these foods in their usual household form and incorporated in introduction schedules. The feasibility of the introduction scales was tested in parents of the children attending our clinic.

RESULTS

Based on the results of the positive challenges (37) in which severe reactions did not occur, detailed introduction schedules and a reference photograph of the required increasing amounts of food were devised for use at home. Feasibility testing showed that, when using these introduction schedules, parents portioned the initial doses significantly lower than without detailed instructions.

CONCLUSIONS

The introduction schedules and reference photograph provide information for parents to introduce the required amounts of allergenic foods in initial low doses at home. This is expected to improve the safety of this procedure.

Parental food allergy information needs: a qualitative study

OBJECTIVE

To examine information needs and preferences of parents regarding food allergy.

DESIGN

Qualitative study including in-depth semi-structured interviews and focus group discussions. Data were audio-recorded, transcribed verbatim and analysed using the constant comparative method, aided by participant checking of interview summaries, independent reviewers and qualitative analysis software.

PARTICIPANTS

84 parents of children with food allergy.

SETTING

Three paediatric allergy clinics and a national consumer organisation.

RESULTS

Most parent participants had received third level education (72%) and 39% had occupational backgrounds in health and education. Parents experienced different phases in their need for information: at diagnosis when there is an intense desire for information, at follow-up when there is continuing uncertainty about allergy severity and appropriate management, and at new events and milestones. They preferred information to be provided in a variety of formats, with access to reliable individualised advice between clinic appointments, within the context of an ongoing relationship with a health professional. Parents wished to know the reasoning behind doctor's opinions and identified areas of core information content, including unaddressed topics such as what to feed their child rather than what to avoid. Suboptimal information provision was cited by parents as a key reason for seeking second opinions.

CONCLUSION

Parents with children with food allergies have unmet information needs. Study findings may assist in the design and implementation of targeted educational strategies which better meet parental needs and preferences.

Government advice on peanut avoidance during pregnancy--is it followed correctly and what is the impact on sensitization?

BACKGROUND

In 1998, the UK government issued precautionary advice that pregnant or breast-feeding women with a family history of atopy, may wish to avoid eating peanuts during pregnancy and lactation. This study aimed to assess the compliance with this recommendation and investigate its impact upon peanut sensitization.

METHODS

A total of 858 children born immediately after the advice were followed for 2 years and assessed for peanut sensitization. A standardized questionnaire was used to ascertain history of atopy and maternal exposure to peanuts during pregnancy. Following parental consent children were skin prick tested to assess sensitization to peanuts.

RESULTS

Sixty-five per cent of mothers had avoided peanuts during pregnancy. Forty-two per cent of the mothers had heard about the government advice, and half modified their diet as a consequence. Neither maternal nor family history of atopy had any significant effect on peanut consumption. Parity did play a role, and mothers having their first child were twice as likely to change their diet (P<0.001). Mothers of 77% of the children sensitized to peanuts had avoided peanuts during pregnancy. In this cohort study maternal consumption of peanut during pregnancy was not associated with peanut sensitization in the infant.

CONCLUSIONS

The majority of mothers in this cohort avoided peanut consumption during pregnancy. It is likely that either the government advice is misunderstood by mothers, or that those who communicate the advice have not fully explained who it is targeted at.

Prenatal versus postnatal sensitization to environmental allergens in a high-risk birth cohort

BACKGROUND

The timing of allergen sensitization is controversial, with conflicting evidence suggesting transplacental priming versus exclusively postnatal priming. Resolution of this question is important in relation to rational design of allergy prevention strategies, particularly the issue of allergen avoidance during pregnancy.

OBJECTIVE

To elucidate the kinetics of sensitization in high-risk children during their first 2 years of life.

METHODS

We prospectively studied house dust mite (HDM)-specific IgE and IgG(4) antibody production and associated T-cell immunity in a cohort of 200 high-risk infants. Parallel antibody studies tracked responses against a broader panel of inhalant and dietary allergens including peanut.

RESULTS

HDM-induced T(H)2 responses in PBMC from 6 months onward, particularly IL-4 and IL-5, correlated increasingly strongly with sensitization outcomes at 2 years, and a contrasting negative relationship was observed with IFN-gamma response capacity. HDM-induced T-cell responses in cord blood, although common, were unrelated to subsequent sensitization. Transient HDM-IgE (and IgG(4)) production frequently peaked at 6 or 12 months before returning to baseline, which suggests the onset of protective tolerance. This finding contrasted with progressively increasing HDM-IgE titers in children sensitized by 2 years of age. Comparably contrasting patterns were observed in peanut-specific responses in sensitized versus nonsensitized children.

CONCLUSION

Priming of T(H)2 responses associated with persistent HDM-IgE production occurs entirely postnatally, as HDM reactivity in cord blood seems nonspecific and is unrelated to subsequent development of allergen-specific T(H)2 memory or IgE.

CLINICAL IMPLICATIONS

These findings question the scientific basis for existing recommendations for allergen avoidance by high-risk women during pregnancy.