INTRODUCTION — Food allergy is best viewed as a chronic condition that does not have a definitive cure and requires lifestyle changes. Those changes traditionally involved avoidance of the allergen, but some patients are opting for novel approaches such as oral immunotherapy (OIT) that may require steady and routine ingestion of low doses of the allergen to remain effective. Regardless of the approach to management, the lifestyle changes as well as anxiety about the possibility of anaphylaxis are the main causes of distress [1]. Thus, improving the patient's and family's quality of life (QoL) is an important long-term management goal for patients with food allergy and their families.
This topic review defines QoL and health-related QoL (HRQoL) and its measurement in practice and in research efforts and discusses the impact of food allergy on HRQoL. We review emerging information on the impact of novel therapies on HRQoL and offer insights on how to try to improve it in practice. A broader overview of HRQoL assessment is discussed separately. (See "Evaluation of health-related quality of life (HRQL) in patients with a serious life-threatening illness".)
QoL AND HRQoL — Quality of life (QoL) is defined by the World Health Organization (WHO) as "an individual's perception of his/her position of life in the context of the culture and value systems in which he/she lives and in relation to his/her goals, expectations, standards, and concerns" [2]. The term "health-related quality of life" (HRQoL) is almost exclusively used to denote patients' perception of the impact of an illness and its therapy on their QoL and daily functioning [3]. HRQoL sometimes overlaps with "health status," which is an objective assessment of impact of illness. However, HRQoL measurement strategies (mainly, questionnaires) do not measure the actual impact as observed objectively. Patients can have similar levels of clinical impairment and yet have widely different perceived HRQoL.
ASSESSMENT — HRQoL looks at the perceived impact of the illness on three broad domains: social, psychological, and physical (see "Evaluation of health-related quality of life (HRQL) in patients with a serious life-threatening illness"). Two types of instruments exist to measure HRQoL: generic and disease specific [4-6]. Generic questionnaires are useful in comparing different diseases, and results may be compared with group norms. In addition, these questionnaires are sensitive to comorbidities. Generic instruments may miss small changes in a patient's impairment over time because they do not incorporate questions directly related to the specific disorder. In contrast, disease-specific instruments cannot be used to compare between different diseases or evaluate comorbidities. However, disease-specific instruments are more sensitive to changes in the illness of interest. Thus, they are more likely to detect changes that result from a treatment or intervention or reveal differences in subgroups of patients with a particular disease. As examples, the impact of food allergy may vary depending upon factors related to type of food, number of food allergies, severity of symptoms, threshold amount of the food needed to trigger a reaction, age or sex of the patient, or cross-cultural differences [4,7]. Most studies of food allergy HRQoL involve samples of predominantly White participants with relatively high socioeconomic status, limiting their generalizability. A list of commonly used instruments is provided. (See 'Food allergy-specific HRQoL Questionnaires' below.)
IMPACT — The burden of avoidance and fear of an accidental exposure can increase anxiety, restrict daily activities, and result in reduced HRQoL for both patients with food allergies and their families. This impact may be perceived differently across groups (eg, parent/caregiver versus child).
Parents/caregivers and families — The impact on parents/caregivers and families is an important aspect of the dysfunction related to psychosocial stress associated with food allergy. Overall, it appears that parents/caregivers perceive that food allergy has a greater impact on the child and family than the child perceives. HRQoL can be compromised by increased disease morbidity and anxiety related to perceived knowledge of the risks associated with food allergy. When evaluating results from self-report questionnaires (such as HRQoL scores), it is important to be mindful of selection bias. If a study does not actively try to recruit a representative sample, it is probable that subjects who choose to answer the questionnaire will significantly skew towards those with a lower perceived HRQoL. Thus, convenience sampling or "internet surveys" will probably result in substantially skewed results that are not necessarily generalizable [8].
Results from one small study using a generic HRQoL instrument suggest that food allergy has a greater impact on the HRQoL of the parents/caregivers than the affected child, with lower QoL overall and in the social relationships domain in the parents/caregivers [9]. Other studies suggest that parents/caregivers perceive food allergy as having a greater impact on their children than other chronic diseases. In one study that compared the HRQoL and family relations of children with peanut allergy to those with rheumatologic disease, parents/caregivers of children with peanut allergy reported that their children had significantly more disruption in their daily activities and greater impairment in normal social interactions compared with parental/caregiver reports of children with rheumatologic disease [10]. A second study, conducted on members of the Food Allergy Network (a parent/caregiver/patient advocacy group), showed that childhood food allergy has a significant impact on general health perception, emotional impact on the parent/caregiver, and limitation on family activities as measured by parental/caregiver perceptions [11,12].
Findings are similar in studies that have used food allergy-specific HRQoL instruments. Parents/caregivers whose children had greater than two food allergies had lower HRQoL than parents/caregivers whose children had fewer allergies [13]. Poorer HRQoL was also seen in caregivers who were more knowledgeable about food allergy, whose children were seen in the emergency department (ED) in the past year for food allergy, or who had children with milk or wheat allergy [14]. Domains affecting families living with food allergy that were identified during the development of this questionnaire included family and social activities, school and camp participation, social activities that involve food, vacationing, eating in restaurants, and finding appropriate childcare [13]. Parents/caregivers felt that anxiety related to the potential risk of a reaction due to accidental ingestion of a food allergen had a more profound impact on emotional and social aspects of a child's everyday life than the effect of an actual allergic reaction triggered by a food allergen [15].
Findings from parent/caregiver focus groups held as part of questionnaire development included the following [16]:
●Mothers found it difficult to entrust others with the care of their child. This led many mothers to quit working outside the home since they felt that they were better able to keep their child safe than other caregivers.
●Marital tensions and conflict were common and stemmed from differences in the level of protection parents/caregivers felt their child needed. Mothers tended to try to shield their child from any possible risk, whereas fathers did not want food allergy to limit a child's life experiences.
●There was also emotional tension due to extended family members' lack of understanding of necessary food allergen avoidance measures and the potential risk of a life-threatening reaction.
●Fear and guilt, as well as anxiety, were common emotions.
●Parents/caregivers were concerned about the possible negative effects of parental/caregiver hypervigilance on their child.
Children — Children overall perceive less of an impact on HRQoL due to food allergies than their parents/caregivers. In one study, children with food allergy had similar to higher QoL scores compared with children without food allergy [9]. In another study, the three most important items related to impairment for children 8 to 12 years of age were [5]: "Must always watch what you eat," "The ingredients of a food change," and "Can eat fewer things."
A European study found that lower QoL in children with food allergy is predicted to some degree by perceived (but not necessarily actual) disease severity, having a peanut or soy allergy, and country of origin [17]. Experiencing anaphylaxis or being prescribed an epinephrine auto-injector did not predict self-reported HRQoL, suggesting again that the perception of severity, not actual severity, of a reaction or the allergy is the important variable. Since both "perceived severity" and HRQoL are elicited by self-reports, those results are perhaps best understood as people who report that their allergy is severe, even if it is not severe, are also likely to report lower HRQoL. "Severity" of food allergy itself is not a well-defined clinical construct [18], as there are no robust markers of severity and a mild reaction at one point in time does not guarantee that the next reaction will also be mild. This lack of clarity probably contributes to distress and reduced QoL in parents/caregivers, who may find the uncertainty stressful. The result is about perception and reporting bias, not necessarily about any objective reality. Supporting this conclusion are results from another study that showed that an actual diagnosis of food allergy does not predict QoL (as compared with perceived but not confirmed diagnosis) [19].
Adolescents — Evaluation of QoL in adolescents is challenging. Some adolescents may perceive their allergy (inaccurately) as nonconsequential, which may lead to low rates of adherence to carrying autoinjectable epinephrine, for example [20]. Thus, when adolescents report a lesser impact of the allergy on their lives, this may simply be misguided, or even an indication of dysfunction, not a true representation of the impact [21]. Indeed, one study reported that HRQoL improves as children become adolescents [22]. A more accurate interpretation of such results may be that it is more worrisome when an adolescent reports a good HRQoL as compared with some impairment, although this proposition has not been studied yet.
Adults — It appears that food allergy adversely affects the HRQoL of affected adults at least as much as other debilitating diseases. Adults with a rheumatologic or allergic disease reported similar HRQoL in one small study [10]. A Dutch study examined the influence of food allergy on adults with peanut, tree nut, and/or fruit allergy [23]. Sixty-three percent of patients rated their food allergy as influencing their daily life at home or outside the home to a very great, great, or important extent. The greatest concerns for adults with food allergies included the inability to identify foods that are safe to eat and the need for improved diagnosis of food allergy [24,25]. These findings are important for care providers, catering industries, and food manufacturers.
Adverse effects of living with food allergy on QOL were examined in a nationally representative sample of 6207 adults in the United States using the Food Allergy Independent Measure (FAIM) via a web- or telephone-based survey [26]. Lower QOL related to food allergy was associated with lower household income, younger age, and higher degree of education as well as history of a severe allergic reaction, a current epinephrine autoinjector prescription or history of use, emergency department visits for food allergy, multiple food allergies, and allergies to wheat, cow's milk, and soy.
EFFECTS OF ORAL IMMUNOTHERAPY ON HRQoL — Oral immunotherapy (OIT) involves ingestion of the allergen in small doses and entails an increased risk for allergic reactions, particularly during the updosing treatment phase in exchange for possible increased tolerance on maintenance therapy. It is suspected that such therapy would affect HRQoL, but it is not clear in which direction and when. Research into effects on HRQoL is still in its infancy and has had mixed results even though OIT is primarily promoted as a way to improve constructs related to QoL such as anxiety. Nearly all of the data are from short-term, observational studies with nonrepresentative (convenience or survey) samples that did not define a primary outcome. Further study in medium-to-long term clinical trials is needed. It is also worth noting that OIT is embraced only by some persons with food allergy and their parents/caregivers. The reasons for choosing OIT rather than simple avoidance are not fully known but are under investigation. It is possible that families that embrace this treatment are hoping for decreased severity of reactions rather than expecting better QoL or less need for avoidance more generally, but, even if so, it is still not clear that OIT can achieve that goal over the long run [27].
One study of 155 children whose parents/caregivers completed HRQoL questionnaires at weeks 1 and 5 of therapy had mixed results, with some parents/caregivers reporting better and some worse HRQoL outcomes for their children during and after OIT compared with baseline [28]. Patients whose parents/caregivers rated them as having worse QoL scores at baseline tended to have an improved score with therapy, whereas those who had a higher QoL at baseline were generally felt to have a decline in QoL with OIT. Another study found an improvement in the QoL of guardians but at the expense of frequent allergic reactions in the children [29], a result that was echoed in another investigation [30]. One randomized trial reported that parents/caregivers of children with food allergy who went through OIT reported that the child's HRQoL improved but that the child's own reports showed no improvement [31]. Another study had the opposite findings, with parent/caregiver reports showing no improvement in child QoL and child reports showing improvement in some domains [32].
EFFECT OF ORAL FOOD CHALLENGES ON QOL — Oral food challenges (OFCs) are attempted in cases in which there is uncertainty about the degree to which an allergen can produce a serious reaction and involve a supervised administration of the allergen in a medical setting [33]. Depending upon pretest probabilities, a certain percentage of patients undergoing OFC experience an anaphylactic reaction, which can be stressful. However, the relative certainty about the presence of allergy and the severity of its impact that is the outcome of most OFCs can lead to improved knowledge about allergy and therefore improved QoL. This can be true even in cases in which anaphylaxis is experienced [34]. It may even be possible to use OFCs as a part of a behavioral intervention that seeks to reduce distress and provide effective education about the management of allergy [35]. The decision to do a food challenge involves the presence of uncertainty, by definition, and it is probable that such challenges may lead to improved QoL only in cases in which such uncertainty leads to substantial prechallenge distress.
INTERVENTIONS TO IMPROVE HRQoL — Behavioral management techniques and educational efforts have been shown to improve HRQoL in other chronic diseases [36,37]. It is therefore possible that targeted behavioral health interventions may not only be effective, but more effective, than other therapies such as oral immunotherapy (OIT) and, in addition, may be less likely to cause adverse effects. However, there are few studies that have examined the effects of interventions specifically aimed at improving HRQoL in patients with food allergy and even fewer such studies that are randomized, controlled trials [38].
There were two randomized trials that attempted to evaluate the effects of behavioral interventions on HRQoL in persons with food allergy. One trial reported nonsignificant improvements in HRQoL following a self-injection procedure aiming to decrease anxiety related to such use amongst teenagers [39]. The other study showed positive effects of targeted education about casual exposure with or without a procedure whereby the participant was asked to touch the allergen [40].
FOOD ALLERGY-SPECIFIC HRQoL QUESTIONNAIRES
Food Allergy Quality of Life - Parental Burden (FAQL-PB) — The first validated food allergy-specific questionnaire was developed to measure parental/caregiver burden in families with a child with food allergy (FAQL-PB) [13,14,41]. This instrument showed the ability to discriminate by disease burden.
Food Allergy Quality of Life Questionnaire - Parent Form (FAQLQ-PF) — The "parent form" allows parents/caregivers to report their child's HRQoL from the child's perspective as perceived by the parent/caregiver [15]. The questionnaire contains three subscales: emotional impact, food anxiety, and social and dietary limitations.
Food Allergy Quality of Life Questionnaire - Child Form (FAQLQ-CF) — The "child form" was the first food allergy-specific questionnaire developed for self-administration by children aged 8 to 12 years with food allergies [5]. This instrument distinguished between children with more than two food allergies and those with less but was unable to discriminate between those with and without a history of anaphylaxis.
The questionnaire was divided into subscales of areas most important in children with food allergy:
●Allergen avoidance (eg, not as easy to have a meal at a friend's house, explaining their food allergy when eating out)
●Risk of accidental exposure (eg, concerns about label reading, watching what foods they touch, people forgetting that they have a food allergy)
●Emotional impact (eg, fear of an accidental exposure, concern that the food allergy will never resolve)
●Dietary restrictions (eg, always having to watch what they eat, more limited in what they can eat, do not get anything when someone brings a special treat to school)
Pediatric Food Allergy Quality of Life (PFA-QL) questionnaire — The PFA-QL questionnaire was the first tool developed for assessing HRQoL in children with food allergy [42]. It was used in several studies [22,43] and was later validated along with the parent/caregiver proxy version (parent form) of the scale (PFA-QL-PF) [44]. These questionnaires have only been used in children with peanut and/or tree nut allergies.
Food Allergy Quality of Life Questionnaire - Teenager Form (FAQLQ-TF) — The "teenager form" was the first disease-specific HRQoL questionnaire for adolescents 13 to 17 years of age with food allergy [5]. Approximately two-thirds of the items on this questionnaire were identical to the "child form," despite the separate development of these tools. In addition, the same three questions had the greatest impact (see 'Food Allergy Quality of Life Questionnaire - Child Form (FAQLQ-CF)' above). Also similar to the "child form," this instrument was able to distinguish between adolescents with more than two food allergies and those allergic to only one food but was unable to discriminate between those with and without a history of anaphylaxis.
The FAQLQ-TF was written and validated in Dutch. It was translated into English and other European languages.
Food Allergy Quality of Life Questionnaire - Teen Form (FAQLQ-teen) — Another HRQoL assessment tool was developed for adolescents aged 13 to 19 years with food allergy in the United States. In the preliminary study of this tool, the adolescents who participated were most concerned about the limitations their food allergy placed on social activities [45]. This instrument, once validated, may help in ascertaining social and emotional concerns and identifying teenagers in need of counseling.
Food Allergy Quality of Life Questionnaire – Adult Form (FAQLQ-AF) — The "adult form" was the first questionnaire developed to measure an adult's HRQoL as it relates to food allergy [24]. The form was written and validated in the Dutch language, and a subsequent online English version was validated in American adults [25].
Food allergy knowledge, attitudes, and beliefs questionnaires — Another validated set of questionnaires addresses food allergy knowledge, beliefs, and attitudes of clinicians, parents/caregivers of children with food allergies, and parents/caregivers of children without food allergies (the general public) [16,46-49].
SUMMARY
●Quality of life (QoL) and health-related quality of life (HRQoL) are subjective constructs and are highly susceptible to reporting bias. It is possible, indeed expected, that two patients with the exact same disease burden would report substantially different QoL. (See 'QoL and HRQoL' above.)
●The burden of avoidance and fear of an accidental exposure can increase anxiety, restrict daily activities, and result in reduced HRQoL for both patients with food allergies and their families. Although measures of food allergy-specific QoL are not validated for use in individual patients, the factors measured should be evaluated routinely in clinical care to address the patient/family holistically. HRQoL is an important target for interventions that purport to reduce the burden of food allergy on patients and families. (See 'Assessment' above and 'Effects of oral immunotherapy on HrQoL' above and 'Food allergy-specific HRQoL Questionnaires' above.)
●Interventions that specifically address HRQoL (eg, by targeted education about casual exposure or by modeling self-injection) can have positive effects on HRQoL and may be used to help manage food allergies. (See 'Interventions to improve HRQoL' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Sally A Noone, RN, MSN, who contributed to earlier versions of this topic review.
