Partially Hydrolyzed Whey Infant Formula: Literature Review on Effects on Growth and the Risk of Developing Atopic Dermatitis in Infants from the General Population

Evaluation of Streptococcus mutans Biofilm Formation and Acidogenicity of Infant Milk Formulas for Treating Cow Milk Allergy: An in vitro Study

INTRODUCTION

When infants cannot consume breast milk, the most commonly available alternative milk formula is cow milk-based. Due to a rise in the prevalence of cow milk protein allergy (CMPA) among children, this study aimed to assess the biofilm formation and acidogenicity of cow milk-based formulas as well as milk formulas suggested for children with CMPA.

METHODS

Cow milk-based formulas with 0%, 10%, or 18% sucrose added, partially hydrolyzed formula (pHF), extensively hydrolyzed formula (eHF), amino acid-based formula (AAF), and soy-based formulas with 0%, or 11% sucrose added were evaluated. Streptococcus mutans was used as a representative microorganism associated with caries. The acidogenicity after 24-h incubation was assessed by the pH of the formed biofilm and lactic acid formation. Biofilm formation was quantified using crystal violet staining. Additionally, the biofilm characteristics were determined using confocal laser scanning microscopy (CLSM). Comparisons were made among formulas without added sucrose to observe protein-based differences. Furthermore, formulas with different sucrose percentages were compared to explore the impact of sucrose content.

RESULTS

When comparing the formulas without added sucrose, the biofilm formation in the cow milk-based formula and pHF were significantly greater than the soy-based formula, eHF, and AAF. In the presence of S. mutans, all formulas reduced the biofilm pH below the critical enamel pH. The cow milk-based formula and AAF showed a significantly lower biofilm pH than the pHF, soy-based, and eHF groups, while the lactic acid production was markedly higher in the cow milk-based formula, pHF and AAF, compared with the eHF and soy-based formula. Adding sucrose into the cow milk-based and soy-based formulas substantially increased biofilm mass. The biofilm pH of the cow milk-based formulas, with or without sucrose, was significantly lower than that of the soy-based formulas. The CLSM indicated distinct biofilm characteristics among the different protein-based formulas, with sucrose supplementation promoting S. mutans aggregation in cow milk-based formula biofilm and increased density and intact biofilm in the soy-based formula.

CONCLUSION

All assessed milk formulas had caries-inducing factors, including those without supplemental sucrose. Among them, the eHF demonstrated the least caries-inducing factors, attributed to its minimal biofilm formation and the highest biofilm pH.

The Impact of Infant Feeding Regimen on Cow's Milk Protein Allergy, Atopic Dermatitis and Growth in High-Risk Infants during the First 6 Months of Life: The Allergy Reduction Trial

The development of early-onset cow's milk protein allergy and atopic dermatitis during the first months of life is multifactorial, including both genetic and nutritional aspects. This study aims to assess the impact of different feeding patterns on the incidence of cow's milk protein allergy, atopic dermatitis, and growth among infants with a family history of allergy. A total of 551 high-risk infants were randomly recruited from 3 European countries in three feeding regimens: exclusive breastfeeding, partially hydrolyzed formula, or standard formula with intact protein either exclusively or supplementary to breastfeeding. During the first 6 months of intervention, amongst infants with a family history of atopic dermatitis, 6.5% of partially hydrolyzed formula-fed infants and 22.7% of exclusively breastfed infants (p = 0.007) presented with atopic dermatitis respectively. Growth as assessed by weight increase did not differ between the aforementioned groups. Although cow's milk protein allergy was not related to the different milk feeding regimens in the whole cohort, when adjusting for high breast milk intake, the respective incident was significantly lower in the infants consuming partially hydrolyzed formula (p < 0.001). This data indicates that a specific partially hydrolyzed formula could serve as a more appropriate complement to breast milk compared to a standard intact protein formula in high-risk infants, to reduce the incidence of atopic dermatitis.

Protein and carbohydrate content of infant formula purchased in the United States

BACKGROUND

The protein and carbohydrate composition of formula fed infants' diets in the United States (US) has not been described. The aims of this study were to characterize these dietary exposures in infant formula purchased in the US and to estimate the proportion of formula purchased which is hypoallergenic or lactose-reduced formula.

METHODS

Powdered infant formula purchase data from all major physical stores in the US prior to the COVID-19 pandemic, between 2017 and 2019, were obtained from Information Resources, Inc. Protein and carbohydrate composition and scoop sizes for each formula were obtained from manufacturers. Ready to feed liquid products, products for premature infants and products for over 1 year old were not included.

RESULTS

Total volumes of term formula purchased were 216 million kg of formula powder (equivalent to 1.65 billion litres) over 3 years. Intact protein formula was 67.9% of formula purchased, 26.6% was partially hydrolysed and 5.5% was hypoallergenic (5.2% extensively hydrolysed protein; 0.3% amino acid based). Soy protein formula represented 5.1% of formula purchased. Carbohydrate content overall was 52.7% lactose, 42.3% glucose polymers and 5.0% sucrose. 23.7% of formula purchased included sucrose as a carbohydrate. Of all formula purchased, 59.0% was lactose reduced, containing a non-lactose carbohydrate. Of 'standard' formula, defined as intact protein, non-thickened, cow's milk formula, 32.3% was lactose reduced. The proportion of hypoallergenic formula purchased significantly exceeded the prevalence of cow's milk protein allergy and increased over the 3-year study period from 4.9% to 7.6% of all formula sold.

CONCLUSIONS

US infants are exposed to unnecessarily high levels of non-lactose carbohydrates and hypoallergenic formula, and this may represent a significant nutritional health risk.

Improvement of functional properties of cow's milk peptides through partial proteins hydrolysis

Allergy by cow's milk proteins is among the major food allergies and could be reduced by the partial hydrolysis of these proteins by proteases, without significantly affecting its physicochemical properties. In addition, the peptides generated through enzymatic hydrolysis of the cow's milk can present prebiotic and bioactive properties. In this work, the cow's milk proteins were submitted to a controlled hydrolysis by Novo-Pro D® and the influence of the degree of hydrolysis (DH) on peptide size distribution was evaluated, as well as the prebiotic and antimicrobial properties of milk hydrolysates. It was shown that for DH-10%, all the peptides have sizes lower than 12 kDa which is the size of the most allergenic proteins, without apparent changes in the milk, as long as heating of the hydrolysate is avoided. The protein hydrolysis promoted a great improvement in the milk functional properties. In addition, the obtained milk peptides presented great prebiotic activities, as indicated by the significant improvement of the growth of prebiotic L. acidophilus and L. reuteri and by the production of bacteriocins indicated by the inhibition halos in the growth of a pathogenic microorganism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05533-x.

Hydrolysierte Säuglingsnahrung für die Allergieprävention – wissenschaftliche Evidenz und Empfehlungen für die Praxis

Hintergrund

Laut S3-Leitlinie „Allergieprävention“ (Update 2021) soll bei nicht (voll) gestillten Säuglingen mit erhöhtem Allergierisiko geprüft werden, ob eine Säuglingsnahrung mit nachgewiesener allergiepräventiver Wirksamkeit verfügbar ist. Einige Hersteller bewerben ihre Produkte entsprechend.

Ziel der Arbeit

Der Artikel gibt einen Überblick über die wissenschaftliche Evidenz und internationale Empfehlungen zum Einsatz von hydrolysierter Säuglingsnahrung (sog. hypoallergene [HA-]Nahrung) zur Prävention von atopischen Erkrankungen.

Materialien und Methoden

In medizinischen Datenbanken wurde eine Literaturrecherche (Zeitraum: 2016–2021) zum Nutzen von hydrolysierten Säuglingsnahrungen für die Allergieprävention bei Risikokindern und zu entsprechenden internationalen Leitlinien durchgeführt. Auf dieser Basis wurden die aktuelle Empfehlung der deutschen S3-Leitlinie sowie die Produkte auf dem deutschen Markt eingeordnet.

Ergebnisse

Es gibt keine hinreichenden Belege für einen generellen allergiepräventiven Nutzen von Säuglingsnahrungen mit Proteinhydrolysat bei Säuglingen mit erhöhtem Allergierisiko. Die GINI-Interventionsstudie deutet darauf hin, dass eine der eingesetzten Hydrolysatnahrungen zur Prävention atopischer Dermatitis bei Risikokindern wirksam gewesen sein könnte. Die Ergebnisse können aber, auch angesichts methodischer Schwächen, nicht als alleinige Basis für eine allgemeine Empfehlung zur Verwendung von HA-Nahrung herangezogen werden. Internationale Fachgesellschaften sprechen sich seit einigen Jahren eher gegen eine solche Empfehlung aus.

Diskussion

Für die derzeit in Deutschland vermarkteten Säuglingsnahrungen auf Basis von partiell hydrolysiertem Protein fehlen Wirksamkeitsbelege. Sie können daher nicht zur Allergieprävention empfohlen werden.

The Risk Reduction Effect of a Nutritional Intervention With a Partially Hydrolyzed Whey-Based Formula on Cow's Milk Protein Allergy and Atopic Dermatitis in High-Risk Infants Within the First 6 Months of Life: The Allergy Reduction Trial (A.R.T.), a Multicenter Double-Blinded Randomized Controlled Study

Background

The role of partially hydrolyzed formulas (pHF) as part of nutritional interventions to prevent the development of allergic manifestations (AM) is questioned, and efficacy of each specific pHF should be substantiated.

Objective

To investigate the risk-reduction effect of a whey-based pHF on the development of cow's milk protein allergy (CMPA) and atopic dermatitis (AD) in infants at high-risk for allergy within the first 6 months of life.

Materials and Methods

In a multicenter double-blinded randomized controlled setting, healthy non-exclusively breastfed full-term infants, received either a specific whey-based pHF or a standard cow's milk-based formula (SF) and were clinically assessed for AM at 2, 4, and 6 months of age, supported by the objective scoring tools SCORAD and CoMiSS. CMPA was confirmed by open food challenge. Intention-to-Treat (ITT) and Per-Protocol (PP) analyses were performed.

Results

Of 331 randomized subjects (ITT analysis set), 160 received the pHF and 171 the SF. Six (3.8%) infants in the pHF and 12 (7%) in the SF group developed CMPA (p = 0.186). AD incidence was significantly lower in those receiving pHF as compared to SF (10.6% vs. 18.7%, p = 0.024) with a relative risk (RR, 95% CI) of 0.54 (0.32, 0.92), in particular when adjusting for family history of AD [6.5% vs. 27.3%, RR 0.24 (0.07, 0.78), p = 0.018] representing a risk reduction of 76%. The PP analysis showed similar results.

Conclusion

This specific whey-based pHF reduced the risk of AD development, particularly in those with a family history of AD, and tended to reduce the development of CMPA in non-exclusively breastfed infants at high-risk for allergy. The A.R.T. study suggests that this particular pHF may contribute to measures aimed at prevention of allergic manifestations. However, further studies are needed to confirm this risk-reduction effect.

Partially Hydrolysed Whey-Based Infant Formula Improves Skin Barrier Function

Specific partially hydrolysed whey-based infant formulas (pHF-W) have been shown to decrease the risk of atopic dermatitis (AD) in infants. Historically, AD has been associated primarily with milk allergy; however, defective skin barrier function can be a primary cause of AD. We aimed to ascertain whether oral supplementation with pHF-W can improve skin barrier function. The effect of pHF-W was assessed on transepidermal water loss (TEWL) and antibody productions in mice epicutaneously exposed to Aspergillus fumigatus. Human primary keratinocytes were stimulated in vitro, and the expression of genes related to skin barrier function was measured. Supplementation with pHF-W in neonatal mice led to a significant decrease in TEWL and total IgE, but not in allergen-specific antibody levels. The whey hydrolysate was sufficient to decrease both TEWL and total IgE. Aquaporin-3 gene expression, linked with skin hydration, was modulated in the skin of mice and human primary keratinocytes following protein hydrolysate exposure. Skin barrier improvement may be an additional mechanism by which pHF-W may potentially reduce the risk of AD development in infants. Further human studies are warranted to confirm the clinical efficacy of these observations.

Peptide Characterization and Functional Stability of a Partially Hydrolyzed Whey-Based Formula over Time

Human clinical trials have shown that a specific partially hydrolyzed 100% whey-based infant formula (pHF-W) reduces AD risk in the first yeast of life. Meta-analyses with a specific pHF-W (pHF-W1) confirm a protective effect while other meta-analyses pooling different pHF-W show conflicting results. Here we investigated the molecular composition and functional properties of the specific pHF-W1 as well as the stability of its manufacturing process over time. This specific pHF-W1 was compared with other pHF-Ws. We used size exclusion chromatography to characterize the peptide molecular weight (MW), a rat basophil degranulation assay to assess the relative level of beta-lactoglobulin (BLG) allergenicity and a preclinical model of oral tolerance induction to test prevention of allergic sensitization. To analyze the exact peptide sequences before and after an HLA binding assay, a mass cytometry approach was used. Peptide size allergenicity and oral tolerance induction were conserved across pHF-W1 batches of production and time. The median MW of the 37 samples of pHF-W1 tested was 800 ± 400 Da. Further oral tolerance induction was observed using 10 different batches of the pHF-W1 with a mean reduction of BLG-specific IgE levels of 0.76 log (95% CI = -0.95; -0.57). When comparing pHF-W1 with three other formulas (pHF-W2 3 and 4), peptide size was not necessarily associated with allergenicity reduction in vitro nor oral tolerance induction in vivo as measured by specific IgE level (p < 0.05 for pHF-W1 and 2 and p = 0.271 and p = 0.189 for pHF-W3 and 4 respectively). Peptide composition showed a limited overlap between the formulas tested ranging from 11.7% to 24.2%. Furthermore nine regions in the BLG sequence were identified as binding HLA-DR. In conclusion, not all pHF-Ws tested have the same peptide size distribution decreased allergenicity and ability to induce oral tolerance. Specific peptides are released during the different processes used by different infant formula producers.

Comparison of the acute metabolic effect of different infant formulas and human milk in healthy adults: a randomized trial

Background/Objectives

Different infant formulas, varying in protein type and quantity, are available for infants who are not breastfed or are partially breastfed. Postprandial insulinemic and glycemic responses to intact vs partially hydrolyzed protein in infant formula are unclear. To compare the effect of different forms (partially hydrolyzed vs non-hydrolyzed) and levels of protein in infant formula compared with a human milk reference subgroup on insulin response in adults.

Subjects/Methods

In a randomized, double-blinded, cross-over study, 35 healthy adults consumed 600 ml of three different infant formulas: Intact protein-based formula (INTACT) (1.87 g protein/100 kcal; whey/casein ratio of 70/30; 63 kcal/100 ml), partially hydrolyzed whey-based formula (PHw) (1.96 g protein/100 kcal; 100% whey; 63 kcal/100 ml), a high-protein partially hydrolyzed whey-based formula (HPPHw) (2.79 g protein/100 kcal; 100%whey; 73 kcal/100 ml) and a subgroup also consumed human milk (HM) (n = 11). Lipid and carbohydrate (lactose) contents were similar (5.1–5.5 and 10.5–11.6 g/100 kcal, respectively). Venous blood samples were taken after overnight fasting and at different intervals for 180 min post-drink for insulin, glucose, blood lipids, GLP-1, glucagon, and C-peptide.

Results

Twenty-nine subjects (eight consuming HM) adhered to the protocol. INTACT and PHw groups had similar postprandial insulinemia and glycaemia (C_max and iAUC) that were not different from those of the HM subgroup. HPPHw resulted in higher postprandial insulin responses (iAUC) relative to all other groups (p < 0.001, p < 0.001, p = 0.002 for the comparison with INTACT, PHw, HM, respectively). HPPHw resulted in a higher glucose response compared to INTACT and PHw (iAUC: p = 0.003, p = 0.001, respectively), but was not different from HM (p = 0.41).

Conclusion

This study in adults demonstrates similar postprandial insulinemia and glycaemia between INTACT and PHw, close to that of HM, but lower than HPPHw, which had a higher protein content compared to the other test milks. The findings remain to be confirmed in infants.

Clinical trial registration

This study is registered at clinicaltrials.gov, identifier NCT04332510.

Variation in Infant Formula Macronutrient Ingredients Is Associated with Infant Anthropometrics

Background: There is wide variation in the macronutrient ingredient base of infant formula. How variation in macronutrient ingredients may impact infant growth remains largely unknown. Methods: The 2015–2016 National Health and Nutrition Examination Survey (NHANES) dataset was utilized, including infant anthropometrics and dietary intake. The protein, fat, and carbohydrate sources of formulas consumed were assembled and considered as potential predictors in multivariable models of infant Z-scores among infants < 6 months, 6–12 months and all infants combined (0–12 months). Results: The following relationships represent ingredient covariates within the final multivariable models of infant Z-scores. Consuming formula with palm oil was associated with higher weight-for-length Z-scores among infants < 6 months, but lower weight-for-age and weight-for-length Z-scores among infants 6–12 months. Consuming soy-protein formulas was associated with lower weight-for-length, head circumference-for-age and abdominal circumference-for-age Z-scores among infants < 6 months. Consuming sucrose-containing formula was associated with higher weight-for-length and abdominal circumference-for-age Z-score among infants 0–12 months. Conclusions: These data provide proof-of-concept that all formulas are not the same. Variation in macronutrient ingredients within the standard formula category is associated with differences in infant anthropometric outcomes. Long-term and mechanistic studies are warranted to pursue these findings; especially for palm oil, soy protein, and sucrose.

What's new in atopic eczema? An analysis of systematic reviews published in 2018. Part 1: prevention and topical therapies

This review is part of a series of annual updates that summarize the evidence base for atopic eczema (AE). The aim is to provide a succinct guide for clinicians on the key findings from 14 systematic reviews on the prevention and topical treatment of AE published or indexed in 2018. Various supplements, including long-chain polyunsaturated fatty acids, vitamin D and the probiotic Lactobacillus rhamnosus GG, given prenatally and postnatally, have not been shown to prevent AE in infants, although mixed strains of probiotics may decrease the risk of AE if given to the mother during pregnancy and to the infant for the first 6 months of life. In the postnatal period, there is no evidence that hydrolysed formula, compared with cow's milk formula (CMF), reduces the risk of AE in partially breastfed infants. However, weak evidence suggests that a specific partially hydrolysed whey formula decreases the risk of AE compared with CMF. No specific skin practices can be recommended to reduce the eczema risk in healthy term babies. There is weak evidence of a low risk of reversible hypothalamic-pituitary-adrenal axis suppression following 2-4 weeks of treatment with low-potency topical steroids, and conflicting evidence as to whether bleach bathing affects skin flora or AE severity. A single study demonstrated that the topical Janus kinase inhibitor tofacitinib at 2% significantly reduces the Eczema Area and Severity Index compared with vehicle. Topical naltrexone cream 1% improves pruritus (measured using a visual analogue scale) by 30% more than placebo. There is weak evidence that topical alternative therapies, including antioxidants, micronutrients and some herbal medicines, may improve AE.

Recent Advances in Clinical Allergy and Immunology 2019

The immune system has vital functions for homeostasis and host defense. Thus, imbalances of the immune system whether associated with allergy, hypersensitivity, or autoimmunity are of great importance, as is manifest from common diseases such as atopic diseases, urticaria, and angioedema, and drug hypersensitivity reactions. These can affect patients' quality of life and can generate high costs for health care. Epidemiological studies have provided evidence for changing patterns of allergic diseases caused by lifestyle and climate changes which have consequences for medical care. Deeper insights into the pathogenesis of allergic/immunologic diseases, combined with novel technologies, provide improved diagnostic options and treatment measures. This review will summarize novel aspects of the epidemiology, pathogenic mechanisms, as well as disease management in the fields of allergy and clinical immunology.

Oral Tolerance Induction to Newly Introduced Allergen is Favored by a Transforming Growth Factor-β-Enriched Formula

Food allergies have become a major healthcare concern, hence preventive efforts to ensure oral tolerance induction to newly introduced antigens are particularly relevant. Given that transforming growth factor-β (TGF-β) plays a key role in immune tolerance, we tested whether an infant formula enriched with TGF-β would improve oral tolerance induction. A partially hydrolyzed whey protein-based formula was enriched with cow's-milk-derived TGF-β (TGF-β-enriched formula) by adding a specific whey protein isolate (WPI). The manufacturing process was optimized to achieve a concentration of TGF-β within the range of human breast milk concentrations. Protection from allergic sensitization and immune response was assessed in a mouse model. Adult mice received the TGF-β-enriched formula, a control non-enriched formula, or water ad libitum for 13 days before sensitization and suboptimal tolerization to ovalbumin (OVA). When compared to non-tolerized mice, suboptimally-tolerized mice supplemented with the TGF-β-enriched formula showed significantly lower levels of total immunoglobulin-E (IgE) and OVA-specific (IgG1). Mouse mast-cell protease-1 (mMCP-1) and cytokine levels were also significantly decreased in suboptimally-tolerized mice fed the TGF-β-enriched formula. In conclusion, oral supplementation with cow's-milk-derived TGF-β decreased allergic responses to newly introduced allergens and thus reduced the risk of developing food allergy.

Food protein amyloid fibrils: Origin, structure, formation, characterization, applications and health implications

Amyloid fibrils have traditionally been considered only as pathological aggregates in human neurodegenerative diseases, but it is increasingly becoming clear that the propensity to form amyloid fibrils is a generic property for all proteins, including food proteins. Differently from the pathological amyloid fibrils, those derived from food proteins can be used as advanced materials in biomedicine, tissue engineering, environmental science, nanotechnology, material science as well as in food science, owing to a combination of highly desirable feature such as extreme aspect ratios, outstanding stiffness and a broad availability of functional groups on their surfaces. In food science, protein fibrillization is progressively recognized as an appealing strategy to broaden and improve food protein functionality. This review article discusses the various classes of reported food protein amyloid fibrils and their formation conditions. It furthermore considers amyloid fibrils in a broad context, from their structural characterization to their forming mechanisms and ensued physical properties, emphasizing their applications in food-related fields. Finally, the biological fate and the potential toxicity mechanisms of food amyloid fibrils are discussed, and an experimental protocol for their health safety validation is proposed in the concluding part of the review.

Whey protein concentrate limits venous thrombosis in rats

To study the influence of whey protein concentrate (WPC-80) on the development of thrombosis, rats were supplemented with 2 doses of WPC-80 (0.3 or 0.5 g/kg) for 7, 14, or 21 days. Then, a 1-h venous thrombosis model was performed in half of the animals. Coagulation parameters, platelet count, and thrombus weight were assessed. Thrombus weight was decreased in rats obtaining WPC-80 and that was significant only for 14- and 21-day supplementation. There were slight differences between groups in coagulation parameters and platelet count but without evident direction. Further research is needed to clarify the observed effects.

A perspective on partially hydrolyzed protein infant formula in nonexclusively breastfed infants

The World Health Organization recommends that infants should be exclusively breastfed for the first 6 months of life to provide optimal nutrition in this critical period of life. After this, infants should receive nutritionally adequate and safe complementary foods while breastfeeding continues for up to 2 years of age or beyond. For nonbreastfed infants, infant formula is an available option to provide the nutrition needed. Infant formula is usually prepared from industrially modified cow’s milk and processed to adjust for the nutritional needs of infants. However, cow’s milk is one of the most common causes of food allergy, affecting 2%–5% of all formula-fed infants during their first year of life. One strategy to prevent cow’s milk allergy in nonbreastfed infants is the use of partially hydrolyzed formula (pHF) in high-risk infants, which are infants born in families with atopic disease. However, based on an epidemiological study, approximately half of the infants who develop allergy are not part of the at-risk group. This is because the non-at-risk group is significantly larger than the at-risk group and the non-at-risk infants have approximately 15% risk of developing allergies. This study aimed to evaluate the effects of partially hydrolyzed whey formula (pHF-W) in nonbreastfed infants and determine whether pHF-W can prevent atopic disease in high-risk infants and can be used as routine starter formula regardless of the allergy risk status.

Recent Advances in Clinical Allergy and Immunology

Allergic diseases are of great concern because of their high prevalence, which is still rising in several regions, their impact on patients' physical and psychological health, the huge burden they place on patients' quality of life, as well as the socioeconomic consequences that they cause. Recent research has provided new data on both genetic and environmental risk factors of atopic/allergic diseases. The application of new technologies such as "omics" has allowed a better understanding of the pathogenesis and has helped with the identification of therapeutic targets. Immense progress has been made in developing and applying novel, targeted therapies, for example for asthma and urticaria. Intensive efforts are being made to find biomarkers that help to classify patients, to identify their potential responsiveness to specific therapies, and to monitor the disease severity. Based on recent insights in the pathogenesis of food allergy and drug hypersensitivity, novel strategies for diagnostics, allergen avoidance, and induction of tolerance have been developed. Here, we summarize important findings in the field of clinical allergy and immunology with a special focus on asthma, allergic rhinitis, atopic dermatitis, food allergy, urticaria, angioedema, and drug hypersensitivity.