The economic impact of peanut allergies

The prevalence of peanut allergies, the most common food allergy in children, has tripled in the past 2 decades. Today, up to 2.5% of the pediatric population has been diagnosed with a peanut allergy. Peanut allergies result in significant medical, out-of-pocket, and opportunity costs to payers, parents, and employers. They are also a leading cause of food allergy-related deaths in children. Although there is evidence that peanut oral immunotherapy may be effective in reducing the severity of the allergy, such approaches require a long intervention with no standardized protocol available. The introduction of biologic compounds to treat peanut allergies has the potential to revolutionize how these patient cases are managed. Their anticipated high cost, however, raises several issues for payers as to how to integrate these new therapies into formularies and treatment continuums.

Severity of peanut allergy and the unmet gaps in care: a call to action

Peanut allergy is one of the most common food allergies in children, with a prevalence that has been increasing over the past several decades. The allergy is a type I, immunoglobulin E (IgE)-mediated reaction that commonly presents in childhood and can be associated with an anaphylactic response. There are many theories that attempt to explain the increasing prevalence, including dietary changes, improvements in hygiene, and intentional allergen avoidance. Diagnosis is made through a combination of a thorough patient history, peanut-specific serum-specific IgE levels, peanut skin-prick test, and, if necessary, an oral food challenge. Guidelines based on the landmark 2015 Learning Early About Peanut Allergy trial suggest that peanuts should be introduced into the diet as early as 4 to 6 months of age in infants who are at highest risk of developing peanut allergy. It is important for providers to recognize risk factors for the development of peanut allergy, identify associated clinical symptoms, and provide an accurate diagnosis of patients to effectively manage them and their families and prevent future reactions.

The National Institutes of Allergy and Infectious Diseases sponsored guidelines on preventing peanut allergy: A new paradigm in food allergy prevention

Peanut allergy is a significant public health problem without proven treatment or cure at present. In 2000, the American Academy of Pediatrics recommended that solid-food introduction be delayed in infants at high risk, including peanut introduction, until age 3 years. In 2008, the American Academy of Pediatrics revised these recommendations based on limited evidence of benefit and, instead, recommended solid-food introduction not be delayed past 4-6 months of life. In 2015, the Learning Early About Peanut Allergy study showed that early peanut introduction (between 4 and 11 months of life) was associated with a significant absolute and relative risk reduction in the development of peanut allergy compared with delayed introduction. Based on these findings, the National Institutes of Allergy and Infectious Diseases sponsored an expert panel to create an addendum to the 2010 Food Allergy Guidelines that specifically focuses on peanut allergy prevention. The addendum recommends that children with severe eczema, egg allergy, or both have peanut introduced as early as 4-6 months of life, after assessment by a trained allergy specialist. For children with mild-to-moderate eczema, peanut can be introduced at ∼6 months, without the need for specialist evaluation. For children with no eczema, peanut can be introduced in accordance with family and cultural preferences, without the need for specialist evaluation. Adherence to these clinical practice recommendations can help potentially reduce the number of cases of peanut allergy per year. However, this can only be accomplished with the cooperation of parents and health care providers who adhere to these recommendations.

Effect of Avoidance on Peanut Allergy after Early Peanut Consumption

BACKGROUND

In a randomized trial, the early introduction of peanuts in infants at high risk for allergy was shown to prevent peanut allergy. In this follow-up study, we investigated whether the rate of peanut allergy remained low after 12 months of peanut avoidance among participants who had consumed peanuts during the primary trial (peanut-consumption group), as compared with those who had avoided peanuts (peanut-avoidance group).

METHODS

At the end of the primary trial, we instructed all the participants to avoid peanuts for 12 months. The primary outcome was the percentage of participants with peanut allergy at the end of the 12-month period, when the participants were 72 months of age.

RESULTS

We enrolled 556 of 628 eligible participants (88.5%) from the primary trial; 550 participants (98.9%) had complete primary-outcome data. The rate of adherence to avoidance in the follow-up study was high (90.4% in the peanut-avoidance group and 69.3% in the peanut-consumption group). Peanut allergy at 72 months was significantly more prevalent among participants in the peanut-avoidance group than among those in the peanut-consumption group (18.6% [52 of 280 participants] vs. 4.8% [13 of 270], P<0.001). Three new cases of allergy developed in each group, but after 12 months of avoidance there was no significant increase in the prevalence of allergy among participants in the consumption group (3.6% [10 of 274 participants] at 60 months and 4.8% [13 of 270] at 72 months, P=0.25). Fewer participants in the peanut-consumption group than in the peanut-avoidance group had high levels of Ara h2 (a component of peanut protein)-specific IgE and peanut-specific IgE; in addition, participants in the peanut-consumption group continued to have a higher level of peanut-specific IgG4 and a higher peanut-specific IgG4:IgE ratio.

CONCLUSIONS

Among children at high risk for allergy in whom peanuts had been introduced in the first year of life and continued until 5 years of age, a 12-month period of peanut avoidance was not associated with an increase in the prevalence of peanut allergy. Longer-term effects are not known. (Funded by the National Institute of Allergy and Infectious Diseases and others; LEAP-On ClinicalTrials.gov number, NCT01366846.).

Peanut allergy in Mexican children: what is the effect of age at first consumption?

Studies suggest that children who start solid foods early are at risk for developing food allergies. Herein, we evaluated the effects of the introduction of peanuts to the diets of children on emerging peanut allergies. Children with allergic rhinitis and asthma were enrolled in the present study and evaluated in four stages. In the first stage, a clinical history was completed for all participants. In the second stage, skin tests were conducted to detect the sensitization to peanuts. In the third stage, the parents were interviewed about the peanut-eating habits of their children. In the fourth stage, children with a convincing history of allergy or a positive peanut skin test result were subjected to an open oral food challenge (OOFC). Three hundred children in four groups were included, 58.2% of the subjects were male, and the mean age was 7.3±3.9 years. The median age of first exposure to peanuts in patients with peanut allergies was greater than that in children without peanut allergies (2 years versus 1 year; p=0.009). The multivariate analysis, including only those children subjected to the OOFC, revealed that the consumption of peanuts after the age of ≥2 years is a risk factor for developing a peanut allergy (odds ratio=8.0, 95% confidence interval 1.3-50.0, p=0.026). The results of the present study showed that the late introduction of peanuts to children increases the risk of developing a peanut allergy.

Natural history of peanut allergy and predictors of resolution in the first 4 years of life: A population-based assessment

BACKGROUND

There are no prospectively collected data available on the natural history of peanut allergy in early childhood. Previous studies of predictors of tolerance development have been biased by failure to challenge high-risk children when IgE antibody levels are high, therefore potentially introducing bias to persistent allergy.

OBJECTIVES

We sought to describe the natural history of peanut allergy between 1 and 4 years of age and develop thresholds for skin prick test (SPT) results and specific IgE (sIgE) levels measured at age 1 and 4 years that have 95% positive predictive value (PPV) or negative predictive value for the persistence or resolution of peanut allergy.

METHODS

One-year-old infants with challenge-confirmed peanut allergy (n = 156) from the population-based, longitudinal HealthNuts Study (n = 5276) were followed up at 4 years of age with repeat oral food challenges, SPTs, and sIgE measurements (n = 103). Challenges were undertaken in all peanut-sensitized children at 1 and 4 years of age, irrespective of risk profile.

RESULTS

Peanut allergy resolved in 22% (95% CI, 14% to 31%) of children by age 4 years. Decreasing wheal size predicted tolerance, and increasing wheal size was associated with persistence. Thresholds for SPT responses and sIgE levels at age 1 year with a 95% PPV for persistent peanut allergy are an SPT-induced response of 13 mm or greater and an sIgE level of 5.0 kU/L or greater. Thresholds for SPT and sIgE results at age 4 years with a 95% PPV for persistent peanut allergy are an SPT response of 8 mm or greater and an sIgE level of 2.1 kU/L or greater. Ara h 2, tree nut, and house dust mite sensitization; coexisting food allergies; eczema; and asthma were not predictive of persistent peanut allergy.

CONCLUSION

These thresholds are the first to be generated from a unique data set in which all participants underwent oral food challenges at both diagnosis and follow-up, irrespective of SPT and sIgE results.

Randomized trial of peanut consumption in infants at risk for peanut allergy

BACKGROUND

The prevalence of peanut allergy among children in Western countries has doubled in the past 10 years, and peanut allergy is becoming apparent in Africa and Asia. We evaluated strategies of peanut consumption and avoidance to determine which strategy is most effective in preventing the development of peanut allergy in infants at high risk for the allergy.

METHODS

We randomly assigned 640 infants with severe eczema, egg allergy, or both to consume or avoid peanuts until 60 months of age. Participants, who were at least 4 months but younger than 11 months of age at randomization, were assigned to separate study cohorts on the basis of preexisting sensitivity to peanut extract, which was determined with the use of a skin-prick test--one consisting of participants with no measurable wheal after testing and the other consisting of those with a wheal measuring 1 to 4 mm in diameter. The primary outcome, which was assessed independently in each cohort, was the proportion of participants with peanut allergy at 60 months of age.

RESULTS

Among the 530 infants in the intention-to-treat population who initially had negative results on the skin-prick test, the prevalence of peanut allergy at 60 months of age was 13.7% in the avoidance group and 1.9% in the consumption group (P<0.001). Among the 98 participants in the intention-to-treat population who initially had positive test results, the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group (P=0.004). There was no significant between-group difference in the incidence of serious adverse events. Increases in levels of peanut-specific IgG4 antibody occurred predominantly in the consumption group; a greater percentage of participants in the avoidance group had elevated titers of peanut-specific IgE antibody. A larger wheal on the skin-prick test and a lower ratio of peanut-specific IgG4:IgE were associated with peanut allergy.

CONCLUSIONS

The early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts. (Funded by the National Institute of Allergy and Infectious Diseases and others; ClinicalTrials.gov number, NCT00329784.).

Food allergy: epidemiology and natural history

The prevalence of food allergy is rising for unclear reasons, with prevalence estimates in the developed world approaching 10%. Knowledge regarding the natural course of food allergies is important because it can aid the clinician in diagnosing food allergies and in determining when to consider evaluation for food allergy resolution. Many food allergies with onset in early childhood are outgrown later in childhood, although a minority of food allergy persists into adolescence and even adulthood. More research is needed to improve food allergy diagnosis, treatment, and prevention.

Peanut allergens

The earliest known evidence of peanut farming dates back 7,600 years. With a prevalence of roughly 1%, peanut allergy is a diagnostic and treatment challenge, but is also a very good model for studying all aspects of food allergy, including its molecular basis and pathomechanisms. Therefore, the very starting point for elucidating all these aspects is the identification of peanut allergens with subsequent clearing of their structure and their preparation as pure recombinant and/or natural allergens. This is the basis for in vitro diagnostic tests as well as the development of immunotherapeutic drugs. With regard to class I food allergy, peanut allergy affects by far the largest group of patients. In peanuts, 12 allergens have been identified and their molecular characteristics are described herein. Ara h 1, Ara h 3.01 and Ara h 3.02 (the former Ara h 4) belong to the cupin superfamily. The conglutins Ara h 2, Ara h 6 and Ara h 7, and the non-specific lipid transfer protein Ara h 9 belong to the prolamin superfamily. Ara h 5 (profilin) and Ara h 8 (Bet v 1-homologous protein) cause class II food allergies and are associated with inhalation allergy to pollen via the sequential and/or conformational similarity of molecules. Two peanut oleosins are listed as Ara h 10 and Ara h 11 and two defensins as Ara h 12 and Ara h 13 by the WHO/IUIS Allergen Nomenclature Subcommittee. The effect of the above-specified allergens has to be considered in the context of their matrix, which is influenced by processing factors and the individual's immune system.

[The prevalence of food allergy to peanut and hazelnut in children in Tomsk Region]

Food allergy to peanuts and nuts is an actual problem of practical health care, associated with significant prevalence of this disease, severe clinical symptoms and difficulty of diet organization. Purpose of the study--to study the prevalence of food allergy to peanut and hazelnut in Russian children, the investigation of clinical characteristics of this disease, and the mechanisms of sensitization to allergen components. The cross-sectional study was performed in the framework of the EuroPrevall (No FP6-2006-TTC-TU-5 Proposal 045879). The first stage was performed in random samples of primary schoolchildren aged 7-10 years (n = 13 010) from the Tomsk Region, Russia using a standardized questionnaire. The case-control sample was recruited for the second stage (n = 1288). Thus who reported adverse reactions to food in the screening stage were considered as cases (n = 652), children without reported reactions were controls (n = 636). The case-control stage included the completion of a clinical questionnaire, skin-prick test (ALK-Abelly, Spain), serum specific IgE measurement and component-resolved diagnostic: IgE measurement of allergen components of peanut (Ara h1, Ara h26, Ara h34, Ara h8), hazelnut (Cor a1, Cor a8, Cor a11) and birch allergen Bet v1 (ImmunoCAP, Phadia, Sweden). The prevalence of food allergy to peanut and hazelnut in children aged 7-10 years in the Tomsk region is 0.08 and 0.09%, respectively. The manifestation of the food allergy to nuts occurs in the preschool years, main reactions associated with allergy to nuts were oral allergy syndrome (75-80%), gastrointestinal disorders (60-80%) and itching skin rash (20-50%). Sensitization to birch is significantly correlated with the level of specific IgE to hazelnut (r = 0.53, p < 0.05) and peanut (r = 0.56, p < 0.05). Sensitization to heat-labile proteins peanut Ara h8 (12.3%) and hazelnut Cor a1 (8.8%) (homologues of Bet v1) dominates in the sample of children with food sensitization, that determines the cross-reactivity mechanism in the formation of food sensitization in the studied sample. The prevalence of allergies to peanut and hazelnut in Russia is much lower than in Europe and North America. Sensitization to these foods develops by the mechanism of cross-reactivity with birch pollen allergen. This type of sensitization determines mild clinical symptoms of allergy to hazelnut and peanut.

[Peanut allergy, not always the correct diagnosis]

BACKGROUND

Diagnosing peanut allergy in children is complicated. The clinical history can be difficult to interpret, measurement of peanut-specific immunoglobulin E (IgE) is of limited usefulness due to its poor specificity, and the gold standard (double-blind placebo-controlled food challenge) is time-consuming and labour-intensive, limiting its use in daily practice. Under-diagnosing peanut allergy is considered dangerous, because of serious reactions like anaphylaxis. As a result, there is a high probability of over-diagnosis of peanut allergy in the general population, leading to unnecessary peanut-free diets and parental anxiety.

CASE DESCRIPTION

We discuss three children diagnosed with peanut allergy, and describe the clinical and diagnostic considerations of peanut allergy. After a detailed history focusing on the reproducibility of objective symptoms after exposure, peanut allergy was excluded in two cases allowing normalization of the diet and reduction of patient and parental anxiety.

CONCLUSION

A detailed history, focusing on reproducible and objective symptoms, is helpful in confirmation or exclusion of the diagnosis 'peanut allergy' and can thus prevent unnecessary peanut-free diets.

IgE-mediated food allergy in children

Food allergy is a serious health issue affecting roughly 4% of children, with a substantial effect on quality of life. Prognosis is good for the most frequent allergens with almost all children outgrowing their allergy. However, the long-term implications for disease burden are substantial for children with persistent allergies (eg, peanuts, tree nuts, fish, and shellfish) and for those with high concentrations of milk, egg, and wheat IgE. Antigen avoidance has been the time-honoured approach both for prevention and treatment. However, findings from studies done in the past 5 years show that early contact with food can induce tolerance and desensitisation to foods. We review the epidemiology, natural history, and management of food allergy, and discuss the areas of controversy and future directions in research and clinical practice.

Parsing the peanut panic: the social life of a contested food allergy epidemic

As medical reports over the last decade indicate that food allergies among children are on the rise, peanut allergies in particular have become a topic of intense social debate. While peanut allergies are potentially fatal, they affect very few children at the population level. Yet, peanut allergies are characterized in medical and popular literature as a rising "epidemic," and myriad and broad-based social responses have emerged to address peanut allergy risk in public spaces. This analysis compares medical literature to other textual sources, including media reports, legislation, and advocacy between 1980 and 2010 in order to examine how peanut allergies transformed from a rare medical malady into a contemporary public health problem. I argue that the peanut allergy epidemic was co-constructed through interactions between experts, publics, biomedical categories, and institutions, while social reactions to the putative epidemic expanded the sphere of surveillance and awareness of peanut allergy risk. The characterization of the peanut allergy problem as an epidemic was shaped by mobility across social sites, with both discursive and material effects.

Peanut allergy diagnoses among children residing in Olmsted County, Minnesota

BACKGROUND

Peanut allergy is a major health concern, particularly in developed countries. Research indicates that as many as 2% of children are allergic to peanuts, which represents a 3-fold increase in diagnoses over the past 2 decades.

OBJECTIVE

This population-based descriptive study used the Rochester Epidemiology Project to estimate the prevalence in 2007 and annual incidence rates of peanut allergy diagnoses from 1999 to 2007 among children residing in Olmsted County, Minnesota.

METHODS

Residents of Olmsted County from January 1, 1999, through December 31, 2007, who received medical care at a Rochester Epidemiology Project facility and provided research authorization were eligible for the study. A medical chart review of 547 potential diagnoses resulted in 244 prevalent and 170 incident cases. Annual rates, crude and adjusted for age and sex, were standardized with the use of the indirect method to the Olmsted County population data in 1999. Incidence rate ratios were estimated with Poisson regression.

RESULTS

The prevalence in 2007 was 0.65%. Female children were less likely to be diagnosed than male children (incidence rate ratio = 0.18; 95% CI, 0.07-0.48). Children aged birth to 2 years were significantly more likely to be diagnosed than older children aged 3-17 years (incidence rate ratio = 0.001; 95% CI, 0.0004-0.004). A significant 3-fold increasing trend was observed in diagnoses over time from 2.05 cases per 10,000 children in 1999 to 6.88 cases per 10,000 in 2007.

CONCLUSIONS

Peanut allergies are an increasing concern in Olmsted County, Minnesota, as indicated by a 3-fold increase in diagnoses from 2.05 per 10,000 children in 1999 to 6.88 per 10,000 children in 2007.

Can we prevent food allergy by manipulating the timing of food exposure?

Prevention of food allergies by maternal and infant feeding practices serves as a simple, inexpensive approach to address the growing number of subjects with food allergies in comparison with any emerging interventional therapies for existing food allergies, such as oral immunotherapy. This article provides a careful evaluation of the rationale and existing data on the effect of timing of the introduction of food allergens (during pregnancy, lactation, and early childhood) on the development of specific food allergies.

Peanut allergy: an evolving clinical challenge

Peanut allergy is an IgE-mediated food allergy responsible for causing severe and occasionally fatal reactions in those sensitized to peanuts. The prevalence of peanut allergy appears to be on the rise worldwide, yet there are no therapeutics currently available that can alter the course of this condition. This article will review the epidemiology, pathogenesis, and clinical features of peanut allergy and discuss future possibilities in diagnostic and therapeutic modalities.