Experiences of double-blind, placebo-controlled food challenges (DBPCFC): a qualitative analysis of mothers' experiences

Diagnostic intervention improved health-related quality of life among teenagers with food allergy

OBJECTIVES

The aim was to examine if a diagnostic intervention set up to assess current food allergy to cow's milk, hen's egg, fish, or wheat among teenagers had an impact on generic and disease specific health-related quality of life (HRQL). The study compared HRQL scoring before and two years after the intervention, and in relation to age matched controls without reported food allergy.

METHODS

The study was performed within the Obstructive Lung Disease in Northern Sweden (OLIN) studies where a cohort study on asthma and allergic diseases among 8-year-old schoolchildren was initiated in 2006. At age 12 years, the 125/2612 (5%) children who reported allergy to cow's milk, hen's egg, fish, or wheat were invited to a diagnostic intervention including clinical examination, blood tests and evaluation by a pediatric allergist. Of 94 participants, 79 completed generic and disease specific HRQL questionnaires. Additionally, a random sample of 200 (62% of invited) children without food allergy from the OLIN cohort answered the generic HRQL questionnaire. The respondents of the HRQL questionnaires were re-examined two years later and 57 teenagers with and 154 without reported allergy participated.

RESULTS

There were no significant differences in generic HRQL scores between teenagers with and without reported food allergy at study entry, or after the intervention. Among those with reported food allergy, we found a significant improvement in disease specific HRQL after the intervention (mean values: 3.41 vs 2.80, p<0.001). Teenagers with only food allergy had better disease specific HRQL compared to those with one, two or three concomitant allergic diseases, both before and after the intervention. Children with only food allergy significantly improved their HRQL after the intervention, 1.84 vs. 2.87 (p<0.001) but this association was not seen in children with one other allergic disorder (3.16 vs. 3.65, p = 0.121) or those with two or more allergic disorders (3.72 vs. 3.90, p = 0.148).

CONCLUSION

The diagnostic intervention showed a long-term improvement of disease specific HRQL but not generic HRQL.

Outcomes of oral food challenges in a real-world setting, with predictors of outcomes

BACKGROUND

Oral food challenge (OFC) remains the reference standard for food allergy (FA) diagnosis.

OBJECTIVE

This study reports a single-center observational experience with all OFCs conducted over 3 years.

METHODS

All OFCs performed at an outpatient office were tracked. The OFCs were conducted without strict prespecified inclusion or exclusion criteria. Demographic information along with results of diagnostic testing and results of the OFCs were recorded.

RESULTS

A total of 1132 OFCs were performed, with a median age of 4 years (interquartile range = 2.0-10.0). Of the 1132 OFCs, 862 (76.1%) tolerated the food, whereas 232 (20.5%) experienced a reaction, and 38 (3.4%) did not complete the OFC because of food refusal. The highest percentage of tolerated food was shellfish (91.1%), with the lowest percentage of tolerated food being baked egg (66.1%). There were 66 (5.8%) OFCs that were deemed to be high risk, of which 35 (53.0%) tolerated the food. More than 50% of reactions occurred on the first or second dose, with the most common clinical symptom being urticaria or angioedema, with 29.2% of reactions treated with epinephrine. There were several factors that predicted tolerating an OFC, including the food challenge, the reason for food avoidance, older age at the time of OFC and less reactive skin prick testing, and lower food-specific immunoglobulin E levels.

CONCLUSION

Certain factors can predict tolerating an OFC, and even those considered to be high risk can be safely completed in an outpatient setting, with most tolerating the food, and most reactions not requiring treatment with epinephrine.

Food-allergy-specific anxiety and distress in parents of children with food allergy: A systematic review

BACKGROUND

Parenting a child with food allergy (FA) can lead to impaired quality of life and family functioning. Anxiety is a critical component of FA-associated distress and a potential target for therapeutic intervention. This systematic review aimed to clarify the concept of FA-specific anxiety (FAA) and its antecedents, consequences, and correlates and to determine the extent to which existing FA-specific outcome measures capture symptoms of parental distress and FAA.

METHODS

MEDLINE, EMBASE, PsycINFO, and CENTRAL were searched for qualitative and quantitative studies examining distress or anxiety in parents of children with FA through August 2020. This review was registered with PROSPERO (CRD42020208316) and conducted in accordance with PRISMA guidelines.

RESULTS

Ninety-eight studies were included in the final narrative synthesis. Most participants were mothers, and reporting of demographic data was limited. Parents identified anxiety as the most burdensome form of FA-specific emotional distress. Several allergy-related factors as well as medical and psychosocial interventions were associated with reduced parental anxiety and distress. However, affective, cognitive, and behavioral dimensions of FAA were only partially addressed by existing measures for general anxiety symptoms and FA-specific parental factors.

CONCLUSIONS

FAA contributes to distress and functional impairment among parents of children with FA. Current FA-specific parent measures fail to adequately capture dimensions of FAA, suggesting that further work is needed to improve the assessment and monitoring of FAA and its impacts. Characterization of this construct represents an initial step in developing standardized methods for assessing and monitoring FAA in clinical populations.

Conducting an Oral Food Challenge: An Update to the 2009 Adverse Reactions to Foods Committee Work Group Report

Oral food challenges are an integral part of an allergist's practice and are used to evaluate the presence or absence of allergic reactivity to foods. A work group within the Adverse Reactions to Foods Committee of the American Academy of Allergy, Asthma & Immunology was formed to update a previously published oral food challenge report. The intention of this document was to supplement the previous publication with additional focus on safety, treatment of IgE-mediated allergic reactions, guidance for challenges in infants and adults, psychosocial considerations for children and families participating in an oral food challenge, specific guidance for baked milk or baked egg challenges, masking agents and validated blinding recipes for common food allergens, and recommendations for conducting and interpreting challenges in patients with suspected food protein-induced enterocolitis syndrome. Tables and figures within the report and an extensive online appendix detail age-specific portion sizes, appropriate timing for antihistamine discontinuation, serum and skin test result interpretation, written consents, and instructional handouts that may be used in clinical practice.

Health Related Quality of Life among schoolchildren aged 12-13 years in relation to food hypersensitivity phenotypes: a population-based study

Background

While Health Related Quality of Life has been investigated among children with IgE-mediated food allergy, less is known about quality of life among children with other types of hypersensitivity to food. The aim of this study was to investigate Health Related Quality of Life (HRQL) in children with and without food hypersensitivity. Further, we compared HRQL between children with different phenotypes of food hypersensitivity.

Methods

In a large population-based cohort of schoolchildren in Northern Sweden, the parents of 2612 (96% of invited) completed a questionnaire. All 125 (5%) children who reported complete elimination of milk, egg, fish or wheat due to food hypersensitivity were invited to a clinical examination and 94 children participated. Of these, 75 children also completed a generic (KIDSCREEN-52) and a disease-specific HRQL questionnaire (FAQLQ-TF). Thereafter, these children were categorised into the different phenotypes: current food allergy, outgrown food allergy, and lactose intolerance. Additionally, 209 children with unrestricted diets answered the generic questionnaire.

Results

The median score of all KIDSCREEN-52 domains were above the population norm of 50 both in children with and without food hypersensitivity. No significant differences in distribution in generic or disease-specific HRQL were found between children with or without food hypersensitivity. There were no significant differences in HRQL between children with different phenotypes of food hypersensitivity. However, children with current food allergy tended to have the lowest HRQL. Further, poor HRQL defined as ≥75th percentile for the disease specific score was significantly more common in the current food allergy phenotype in the domain Emotional impact and the total FAQLQ, compared to the other phenotypes.

Conclusions

In this population-based study, 12–13 year old children reported good HRQL regardless of having food hypersensitivity or not. However, the children with the current phenotype reported lower HRQL than the other phenotypes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13601-017-0156-9) contains supplementary material, which is available to authorized users.

Assessment of children's nutritional attitudes before oral food challenges to identify patients at risk of food reintroduction failure: a prospective study

BACKGROUND

Inappropriate dietary eliminations may impair quality of life, affect children's growth and unnecessarily impact on healthcare costs. Previous retrospective studies reported that around 25% of children continue a food-avoidance diet despite a negative oral food challenge (OFC). A definite pattern has not been found yet for patients not reintroducing the food. This study aimed to examine the role of child's nutritional attitudes and maternal anxiety in reintroducing food after a negative OFC.

METHODS

A prospective study was conducted involving 81 mothers of children with IgE-mediated food allergy. They completed a survey on nutritional behaviour and attitudes and the State-Trait Anxiety Inventory on the day of OFC and 6 months later.

RESULTS

In total, 11.1% of children never or rarely ate the food after a negative OFC. Consumption of the reintroduced food is positively correlated to child's interest in tasting new foods before and after OFC and to changes in child's nutritional habits after OFC. It is negatively correlated to monotony of the diet after OFC. No correlations were found with other participants' characteristics or maternal anxiety. State anxiety significantly decreased after the OFC. A correlation was found between trait and state anxiety and the degree of change in nutritional habits after OFC.

CONCLUSIONS

Evaluating child's approach towards food before the OFC is a promising approach to identify patients at risk of food reintroduction failure. Furthermore, it underlined the importance of reassessing food consumption in all patients after a negative OFC and supporting patients in the reintroduction of food.

Reintroduction failure is common among adolescents after double-blind placebo-controlled food challenges

AIM

There has been a lack of research on adolescents who undergo double-blind placebo-controlled food challenges. The aim of this study was to investigate food allergic adolescents' experiences and consequences of double-blind placebo-controlled food challenges.

METHODS

This qualitative, descriptive interview study included 17 adolescents aged 14-15 years with total elimination of cows' milk, hens' eggs or cod due to food allergies. The participants, who were initially identified from a large population-based cohort study, were interviewed 18 months after completing their challenges.

RESULTS

The double-blind placebo-controlled food challenge proved to be a complex experience for the adolescents, involving fear of potential reactions and the hope that the food could be reintroduced. Experiences during the challenge were described in three themes: facing fears in a secure environment, being hesitant but curious about unknown tastes and waiting for unknown food reactions. Experiences after the challenge were described in two themes: gaining control and freedom and continuing old habits. A negative challenge was not consistently associated with the reintroduction of the challenged food.

CONCLUSION

This study highlighted the importance of considering the adolescents' expectations and experiences of the challenge and the reintroduction process to ensure desirable changes in their dietary habits. Follow-ups should be performed regardless of the outcome of challenges.

A review of oral food challenges in children presenting to a single tertiary centre with perceived or true food allergies

INTRODUCTION

The prevalence of perceived food allergies exceeds that of true food allergies. Unnecessary food avoidance may increase parental and patient anxiety, reduce quality of life and increase the risk of nutritional deficiency. An oral food challenge (OFC) can provide an objective measure regarding the presence or absence of food allergies in a child. This study reviews the indications for and outcomes of OFCs performed on children.

METHODS

A retrospective review was performed on all children who underwent OFCs at the Allergy Unit of the National University Hospital, Singapore, over a three-year period.

RESULTS

A total of 197 OFCs were performed among 58 patients (34 male, 24 female). Most of the tests were for allergies to tree nuts (n = 107). Among the OFCs, 43.1% were for foods that were avoided and never eaten due to perceived food allergies, 25.9% were for foods that had previously resulted in positive skin prick tests (SPTs) and/or immunoassay results, 16.2% were for foods thought to worsen eczema and 14.7% were for foods thought to have caused a previous reaction. Of all the OFCs, 5% were positive, although adverse reactions were mostly cutaneous. Challenge-positive patients had either positive SPTs (wheal > 3 mm) or raised serum immunoglobulin E levels to specific foods that they reacted to during the challenges. No episodes of anaphylaxis were reported after the challenge. Most of the patients were able to safely introduce the avoided foods into their diets.

CONCLUSION

OFCs provide an objective assessment for suspected food allergies.

Mental health and quality-of-life concerns related to the burden of food allergy

As food allergy increases, more research is devoted to its influence on patient and family mental health and quality of life (QoL). This article discusses the effects on parent and child QoL, as well as distress, while appraising the limitations of knowledge given the methods used. Topics include whether QoL and distress are affected compared with other illnesses, assessment of distress and QoL in parents compared with children, concerns about food allergy-related bullying, and the necessity for evidence-based interventions. Suggestions are offered for how to improve QoL and reduce distress on the way to better coping with food allergy.

How mothers perceive infants with unspecific gastrointestinal symptoms suggestive of cow's milk allergy?

AIM

To determine whether specific infant behavioural characteristics are present in children suspected of cow's milk allergy because of gastrointestinal symptoms.

METHODS

We prospectively recruited 57 children (median age 8.7 months) with a suspicion of gastrointestinally manifested cow's milk protein allergy (GI-CMPA). None had detectable cow's milk-specific IgE. Mothers were asked to complete the Parenting Stress Index (PSI) Child Domain, and those with children below 18 months of age (n = 49) also the Infant Temperament Questionnaire (ITQ). GI-CMPA was diagnosed with the double-blind, placebo-controlled food challenge. Control group (n = 22) consisted of patients (age range 4-26 months), attending the Pediatric Allergy Unit, who did not have diagnosed or suspected food allergies.

RESULTS

The scores were significantly higher for the PSI (n = 48) Child Domain (p < 0.0001) and for the ITQ (n = 44) subscale Difficultness (p = 0.0045) compared with the control patients without suspected/diagnosed food allergy. The difference between the challenge positive (n = 18) and negative (n = 39) patients remained statistically insignificant. After 6 months, in both groups, the scores (PSI Child Domain p = 0.0004, ITQ Difficultness p = 0.0393) were lower, but the ITQ Difficultness score still remained higher than in the controls (p = 0.0453).

CONCLUSION

The mothers often perceive infants with unspecific symptoms suggestive of GI-CMPA as demanding and temperamentally difficult.

Food allergy and quality of life: what have we learned?

Health-related quality of life (HRQL) has become an emerging focus of interest in food allergy. Food allergy is a disease characterized by low mortality and symptoms which only occur during an allergic reaction. However, food-allergic patients continuously need to be alert when eating in order to prevent potentially severe allergic reactions, which may be fatal. Fear of such reactions and the need to be continuously vigilant may seriously compromise their HRQL. During the last decade, numerous studies have been published on food allergy and HRQL. The development of reliable, valid and responsive instruments for measuring HRQL in food allergic patients has facilitated this research even further. Such instruments have given insight into the specific problems a patient may face and the impact of food allergy-related interventions from the patient's perspective. This paper focuses on the most significant findings regarding this topic since its first appearance in the literature in 2000.

How mothers interact with children with suspected cow's milk allergy symptoms

AIM

To characterize mother-child interaction in children with suspected gastrointestinally manifested cow's milk allergy (GI-CMA) and to explore factors associated with the parentally perceived symptoms.

METHODS

We invited a randomly selected group of children with suspected GI-CMA and their mothers to take part in a video recording of them playing together. The mother-child interaction was rated using the Emotional Availability Scales (EAS, 4th edition) and compared with national normative data.

RESULTS

Video recordings were conducted with 24 patients (15 girls and nine boys) with a median age of 10.1 months (range 2.1-20.5 months) undergoing a double-blind, placebo-controlled food challenge for cow's milk allergy. The EAS profile in the challenge negative group (17/24) was significantly different from the normative data. The scores for maternal sensitivity (p = 0.0049) and nonintrusiveness (p = 0.0192), together with child responsiveness (p = 0.0053) and involvement of mother (p = 0.0085), were all significantly lower when compared to the normative data. The dimensions of maternal nonhostility and structuring, as well as the scores of the challenge positive group, did not differ from the normative data.

CONCLUSION

Dysfunctional mother-child emotional interaction was frequent in young children with suspected GI-CMA ruled out by the cow's milk challenge. Appropriate psychological support should be considered.

Food avoidance in children with adverse food reactions: influence of anxiety and clinical parameters

BACKGROUND

Many children in the general population avoid food because of self-reported adverse food reactions (AFR). Food avoidance can have negative consequences for well-being and nutritional status. This study aimed to investigate which factors are related to avoidance behavior in children (10-13 yr old) from the general population.

METHODS

Questionnaires for both mother and child were sent to participants from the Europrevall study: 164 children with self-reported AFR and 170 children without AFRs. Spielberger state anxiety and trait anxiety and clinical parameters, such as severity of the adverse reaction, specific IgE and doctor's diagnosis, were compared between those who have (had) AFR and avoid food (i.e., avoiders) and those who have (had) AFR(s) and do not avoid food (anymore; i.e., non-avoiders).

RESULTS

In total, 59% of the children with AFRs avoided food, of whom 26% had positive specific immunoglobulin E (sIgE). Child's state anxiety about an AFR was higher in avoiders than in non-avoiders, (p < 0.001), whereas child's trait anxiety and maternal state anxiety and trait anxiety were comparable in both groups. Avoiders reported more often severe symptoms (i.e., generalized urticaria, respiratory or cardiovascular symptoms) than non-avoiders, (p = 0.03). Food avoidance was not associated with doctor's diagnosis of food allergy or doctor's advice to avoid food (p = 1.00).

CONCLUSION

Food avoidance is related to child's state anxiety about an adverse food reaction. Food avoidance seems to be independent of a doctor's diagnosis of food allergy and advice on food avoidance.

Cow's milk-associated gastrointestinal symptoms evaluated using the double-blind, placebo-controlled food challenge

OBJECTIVE

The aim of this study was to evaluate the suspicion of cow's-milk allergy in infants with unspecific gastrointestinal (GI) symptoms using the double-blind, placebo-controlled food challenge.

METHODS

A prospective cohort study, which recruited 57 consecutive children with gastrointestinally manifested symptoms suspected of cow's-milk allergy. All patients underwent a 5-day double-blind, placebo-controlled food challenge for cow's milk.

RESULTS

The median age of the patients was 8.7 months. None had measurable cow's-milk-specific IgE. The food challenge was positive in 18 (32%) cases, with symptoms manifesting within 48 hours in 17 of 18 cases. The only symptom that correlated with the positive challenge was loose stools, reported as a presenting symptom in 78% of challenge-positive and in 46% of challenge-negative children (P = 0.043). During active challenge, the respective proportions were 82% and 2% (P < 0.0001). No serious adverse effects were manifested during the challenges. In the challenge-negative group, significant placebo reactions occurred in 18 (46%) patients. In the challenge-negative children, adult-type hypolactasia genotype CC frequency was higher (31%, P = 0.033) than national prevalence of 18%.

CONCLUSIONS

In an infant with unspecific GI symptoms suspected of cow's-milk allergy, this diagnosis is seldom confirmed. Other reasons for the troublesome GI symptoms should also be identified.

Maternal intolerance of uncertainty, anxiety, and adherence with food challenge referrals

Anxiety regarding food challenges may serve an important role in parents’ decisions to adhere to their child’s food challenge referrals. This study examined the role of intolerance of uncertainty in food challenge referral adherence by assessing state/trait anxiety among mothers whose children were referred for a food challenge. Mothers whose children passed a food challenge reported significant decreases in anxiety regarding allergic reactions, but intolerance of uncertainty did not predict adherence. Trust in the physician was a primary reason mothers attended the food challenge, suggesting that physicians should consider the impact of the physician–patient relationship when treating these families.

Food allergy-related quality of life after double-blind, placebo-controlled food challenges in adults, adolescents, and children

BACKGROUND

Currently, the longitudinal validity (validity over time) and responsiveness (ability to measure change over time) of the Food Allergy Quality of Life Questionnaire-Adult Form (FAQLQ-AF), the Food Allergy Quality of Life Questionnaire-Teenager Form (FAQLQ-TF), and the Food Allergy Quality of Life Questionnaire-Child Form (FAQLQ-CF) are unknown. Additionally, the self-reported impact of a double-blind, placebo-controlled food challenge (DBPCFC) on health-related quality of life (HRQL) in adults (≥18 years of age), adolescents (13-17 years of age), and children (8-12 years of age) is unknown.

OBJECTIVE

The aims of this study were to assess the longitudinal validity and responsiveness of the FAQLQ-AF, FAQLQ-TF, and FAQLQ-CF and to assess the impact of a DBPCFC on HRQL.

METHODS

Two hundred twenty-one participants suspected of food allergy were included from Dutch allergy centers. Participants undergoing a DBPCFC (experimental group) completed the FAQLQ and Food Allergy Independent Measure (FAIM) 1 month before (baseline) and 6 months after (follow-up) a DBPCFC. Participants not undergoing a DBPCFC (control group) completed the questionnaire package twice with a 7-month interval.

RESULTS

HRQL scores improved after a DBPCFC, with greater improvements in HRQL scores after a negative outcome (food allergy ruled out) than a positive outcome (food allergy confirmed), demonstrating responsiveness of the FAQLQs. Significant correlations were shown between the change (follow-up minus baseline) in FAQLQ and FAIM scores supporting longitudinal validity of these questionnaires: FAQLQ-AF (Pearson correlation coefficient = 0.71, P < .001), FAQLQ-TF (Pearson correlation coefficient = 0.35, P = .018), and FAQLQ-CF (Pearson correlation coefficient = 0.51, P < .001).

CONCLUSIONS

Our findings demonstrate the longitudinal validity and responsiveness of the FAQLQs. Greater improvements in HRQL scores were shown after a negative outcome than after a positive outcome.

Quality of life measures for food allergy

Food allergy has become an emerging health problem in Western societies. Although food allergy is characterized by a relatively low mortality and an almost continual absence of physical symptoms, food allergic patients are continually confronted with the possibility of potentially severe reactions and the necessity of dietary vigilance. Health-related quality of life (HRQL) may be the only meaningful outcome measure available for food allergy measuring this continuous burden. HRQL may be measured with generic or disease-specific instruments. Generic instruments may be relatively unresponsive to differences or changes in health status, whereas disease-specific instruments are generally more sensitive for relatively subtle problems related to a particular illness. Recently, a number of disease-specific questionnaires have become available to measure the HRQL of food allergic patients. An important area for further research is the interpretation of the outcome of HRQL measures. In this respect, the minimal clinically important difference (MCID) is of special interest. In combination with the numbers needed to treat (NNT), this may give an ultimate insight into the clinical relevance of an intervention. Since there is still no cure for food allergy, the only available treatment is strict avoidance of the culprit food and provision of emergency treatment. The double-blind placebo-controlled food challenge (DBPCFC) is considered to be the gold standard for diagnosing food allergy. A number of studies have investigated the perceptions of parents whose children underwent a DBPCFC. In contrast to the parental perception, there is much currently still unknown about the effects of undergoing a DBPCFC in the perceptions of patients. In addition to the research on MCID and NNT of food allergy HRQL questionnaires, further research should focus on deriving quality-adjusted life years (QALYs) from food allergy HRQL questionnaires and the application of food allergy HRQL questionnaires at the individual patient level in clinical practice.

Mental health and quality-of-life concerns related to the burden of food allergy

As food allergy increases, more research is devoted to its influence on patient and family mental health and quality of life (QoL). This article discusses the effects on parent and child QoL, as well as distress, while appraising the limitations of knowledge given the methods used. Topics include whether QoL and distress are affected compared with other illnesses, assessment of distress and QoL in parents compared with children, concerns about food allergy-related bullying, and the necessity for evidence-based interventions. Suggestions are offered for how to improve QoL and reduce distress on the way to better coping with food allergy.