Pearl barley belongs to the barley family. It has been reported that there is a cross-reactivity between wheat and barley. Thus, some children with an immediate-type wheat allergy may also have barley allergies.

A 5-year-old boy was diagnosed with wheat allergy at 7 months, and anaphylaxis occurred with 15 g of wheat noodles in an oral food challenge (OFC) at 4 years of age. After 90 minutes of ingesting curry and rice including pearl barley, he developed anaphylaxis and was brought to the hospital. Specific IgE antibody levels (sIgE) were barley, 56.8; wheat, > 100; ω-5-gliadin, 4.68; gluten, > 100, respectively (all units in U_A/mL). OFC was performed with approximately 8.6 g of pearl barley. He developed cough, wheezing, and skin itching, so he was diagnosed with barley allergy.

Predictive parameters for barley allergy in wheat-allergic children have been reported to be wheat sIgE, ω-5 gliadin sIgE, and severity of wheat OFC. Our patient exceeded these cutoffs and was at high risk for barley allergy. However, under Japanese law, barley does not have to be labeled as an allergy-causing food. Therefore, we should realize that barley may be served blindly to patients as rice containing pearl barley.

Acute food protein-induced enterocolitis (acute FPIES) -related oral food challenges (OFC) have not been systematically studied; high-quality studies providing insight into the relationship between various conditions (i. e, dosing regimen, severity of previous symptoms, loading dose) and the severity of symptoms induced by OFC are lacking; and even in the international consensus guideline of FPIES, the methodology is not fully established. We report a case of a 3-month-old boy. The infant was asymptomatic on mixed feeding until 1 month of age but developed symptoms suggestive of mild acute FPIES upon ingestion of plain milk at 3 months of age. We performed OFC to confirm the diagnosis using loading dose according to the international consensus guidelines but severe symptoms including loss of consciousness and acidosis appeared. FPIES-related OFCs in infants should be conducted with caution, especially when the time is short from the last episode. Given the potential for severe reactions, preparation for emergent situation is needed even when performed using guideline dosage regimen. The methodology for FPIES-related OFCs is yet to be standardized, and accumulation of further evidence is awaited.

Objective: This study explored the needs of caregivers of children with allergic diseases by analyzing text of questions posted on social networking services (SNS).

Methods: Questions assumed to have been asked by caregivers about childhood allergies were extracted from Yahoo! Chiebukuro data (provided by the National Institute of Informatics) and analyzed using text mining techniques.

Results: From a total of approximately 2.7 million questions, 707 were selected by keyword search and direct review by 3 researchers, and words were extracted by morphological analysis. In simple tabulation, many of the words were related to skin and diet. In multidimensional scaling methods, these words and respiratory symptoms-related words were distributed around words related to treatment and those that seek answers. When the words were categorized into hypothesized concepts by code definitions, the concepts that frequently appeared were those relating to anxiety/questioning and hospital visits, followed by skin symptoms. In co-occurrence network analysis, the anxiety/questioning and hospital visit concepts were connected to each other with skin symptoms, atopy, diet, environment, sleep, family relationships, and social life. Respiratory-related concepts strongly co-occurred with each other and weakly with other concept groups.

Conclusion: Caregivers' needs posted to SNS may be high for skin issues related to various aspects of life.

Exercise-induced laryngeal obstruction (EILO) is a condition that causes paroxysmal wheezing and dyspnea during high-intensity exercise. It is a form of inducible laryngeal obstruction (ILO). The laryngeal obstruction is caused due to inappropriate adduction of the supraglottic structures and/or adduction of the vocal cords, which should open during inspiration. It has been described by various terms such as vocal cord dysfunction (VCD), paradoxical vocal cord motion (PVFM), and laryngomalacia. Recently, these terms have been unified. The diagnosis is confirmed by continuous laryngoscopy during exercise (CLE), but only a limited number of facilities can perform CLE.

This condition is often treated as exercise-induced asthma. Hopefully, the awareness about this disease will increase with further studies.

Food protein-induced enterocolitis syndrome (FPIES) is a type of non-IgE-mediated food allergy that can be characterized by repeated vomiting not accompanied by IgE-mediated reactions, such as skin or respiratory symptoms, within 1-4 hours from the time of ingestion of the causative food product. Since the publication of the international consensus guidelines in 2017, reports on FPIES have increasingly been published by countries across the world. In most countries, the most frequent causative foods that cause FPIES include cow's milk, rice, fish, as well as hen's egg. In Japan, the incidence of FPIES caused by hen's egg, especially egg yolk, has been rapidly increasing since the last few years. Consequently, Japan has been leading the research on hen's egg-induced FPIES in terms of its epidemiological factors, such as age of onset and prognosis. However, much remains unknown about the causative antigens, route of sensitization, and vomiting and immunological mechanism. In addition, no established protocols are available for its diagnostic testing, safe and reliable oral food challenges, and long-term management. We hope to curb the increase in number of patients experiencing hen's egg-induced FPIES by clarifying these points in the future.

Molecular-targeted drug refers to the therapeutic drugs developed to target specific molecules involved in the pathogenesis of diseases. It consists of high molecular weight compounds such as monoclonal antibodies and low molecular weight compounds such as JAK inhibitor and PDE4 inhibitor.

Since molecular-targeted drug targets specific molecules involved in pathogenesis, it often dramatically improves symptoms in patients resistant to conventional treatments. On the other hand, allergic diseases are not homogeneous but consist of a heterogeneous population. Therefore, some patients respond well to specific molecular-targeted drug, and patients do not. It is necessary to stratify the patients with allergic diseases based on pathological mechanisms and select the optimal treatment for each subgroup.

In the Japanese Guidelines for Food Allergy (JGFA) 2021, the new chapter 12-9, 10, 11, 12 were added to cover allergies to crustaceans, mollusks, fish, fish roe, fruits, and vegetables. Crustacean, fish, fish roe, and fruit allergies are commonly encountered in clinical practice and can sometimes cause severe symptoms. In addition, because there is less data on their natural history than in the case of hen egg or milk allergy, and affected patients are often sensitized to a wide variety of foods due to the strong cross-reactivity of the major allergens, these patients tend to eliminate them more often than may be warranted.

Chapter 12 explained the age of onset, clinical type classification, prognosis, allergen components, diagnosis, and dietary treatment based on the latest data. We hope that this guideline will deepen the understanding of crustacean, mollusk, fish, fish roe, fruit, and vegetable allergens and will lead to more appropriate dietary treatment based on diagnosis.

This article describes the major changes in the section on food-dependent exercise-induced anaphylaxis (FDEIA) in the 2021 Japanese Guidelines for Food Allergy based on the 2016 guidelines.

The 2016 guidelines defined FDEIA as a "disease" in which anaphylaxis is induced by exercise after ingestion of certain foods. However, in clinical practice, we often experience a patient with FDEIA suffering from allergic symptoms that are triggered by cofactors other than exercise or when at rest. In recent years, several important studies have been reported in relation to the pathogenesis of FDEIA. These studies have shown that exercise is one of the factors that can lower the symptom elicitation threshold for immediate-type food allergies, and that patients thought to have FDEIA can have their symptoms triggered by factors other than exercise. Based on these findings, the 2021 guidelines define FDEIA as a "condition" in which anaphylaxis is triggered by exercise exertion after ingestion of certain foods.

New food allergies caused by sensitization to non-food allergens are recently emerging and are getting known in clinical practice. As a result, the Japanese guideline for food allergy 2021 updates information on food allergies caused by non-food antigen sensitization in a separate chapter (chapter 14). Information on protein families involved in cross-reactivity has been included in Chapter 14-1. In Chapter 14-3, pork-cat syndrome and bird-egg syndrome were newly discussed as food allergies, which pet owners potentially create. In Chapter 14-4, descriptions of animal meat allergy caused by α-Gal after the tick bite and natto allergy caused by poly gamma glutamic acid after jellyfish sting were included as food allergies associated with animal bites. This review concentrates on the theoretical underpinnings and clinical characteristics of food allergies caused by sensitization to non-food allergens.

Allergy to nonfood substances can be a cause of diet-related allergic symptoms. In the 2021 guidelines, a new chapter was created to address such disorders, including allergies to erythritol, cochineal dye, and Anisakis, as well as oral mites (commonly known as oral mite anaphylaxis or pancake syndrome). In this article, the concept, diagnosis, and lifestyle guidance for these diseases are reviewed. In particular, Anisakis allergy is an extremely common cause of anaphylaxis in adults, and should always be considered a cause of allergic symptoms after seafood consumption.

Gastrointestinal food allergies and related diseases, including non-IgE-mediated gastrointestinal food allergies (non-IgE-GIFAs), eosinophilic gastrointestinal disorders (EGIDs), and gluten-sensitive enteropathy, are described in Chapter 16 of the 2021 Japanese Guidelines for Food Allergy (JGFA). These are based mainly on two recently published Japanese guidelines for non-IgE-GIFAs and EGIDs, and international consensus guidelines for a non-IgE-GIFA, food protein-induced enterocolitis syndrome. Herein, the modifications from the previous guidelines, JPGFA2016, and the new information added have been explained in consideration of the current state of clinical practice in Japan.