Gastrointestinal Food Allergy in Infants

Food allergies are classified into three types, “IgE-mediated,” “combined IgE- and cell-mediated” and “cell-mediated/non-IgE-mediated,” depending on the involvement of IgE in their pathogenesis. Patients who develop predominantly cutaneous and/or respiratory symptoms belong to the IgE-mediated food allergy type. On the other hand, patients with gastrointestinal food allergy (GI allergy) usually develop gastrointestinal symptoms several hours after ingestion of offending foods; they belong to the cell-mediated/non-IgE-mediated or combined IgE- and cell-mediated food allergy types. GI allergies are also classified into a number of different clinical entities: food protein-induced enterocolitis syndrome (FPIES), food protein-induced proctocolitis (FPIP), food protein-induced enteropathy (Enteropathy) and eosinophilic gastrointestinal disorders (EGID). In the case of IgE-mediated food allergy, the diagnostic approaches and pathogenic mechanisms are well characterized. In contrast, the diagnostic approaches and pathogenic mechanisms of GI allergy remain mostly unclear.In this review, we summarized each type of GI allergy in regard to its historical background and updated clinical features, offending foods, etiology, diagnosis, examinations, treatment and pathogenesis. There are still many problems, especially in regard to the diagnostic approaches for GI allergy, that are closely associated with the definition of each disease. In addition, there are a number of unresolved issues regarding the pathogenic mechanisms of GI allergy that need further study and elucidation. Therefore, we discussed some of the diagnostic and research issues for GI allergy that need further investigation.     

Food allergies and food intolerances

Adverse reactions to foods, aside from those considered toxic, are caused by a particular individual intolerance towards commonly tolerated foods. Intolerance derived from an immunological mechanism is referred to as Food Allergy, the non-immunological form is called Food Intolerance. IgE-mediated food allergy is the most common and dangerous type of adverse food reaction. It is initiated by an impairment of normal Oral Tolerance to food in predisposed individuals (atopic). Food allergy produces respiratory, gastrointestinal, cutaneous and cardiovascular symptoms but often generalized, life-threatening symptoms manifest at a rapid rate-anaphylactic shock. Diagnosis is made using medical history and cutaneous and serological tests but to obtain final confirmation a Double Blind Controlled Food Challenge must be performed. Food intolerances are principally caused by enzymatic defects in the digestive system, as is the case with lactose intolerance, but may also result from pharmacological effects of vasoactive amines present in foods (e.g. Histamine). Prevention and treatment are based on the avoidance of the culprit food.     

Discrepancies between reported food intolerance and sensitization test findings in irritable bowel syndrome patients

OBJECTIVE: Irritable bowel syndrome (IBS) is a common gastrointestinal disorder with clinical signs typical of "intestinal" food allergies or intolerance. The aim of this study was to characterize the clinical features of IBS patients suspected of suffering from adverse reactions to food. METHODS: The study involved 128 consecutive IBS patients divided into four groups according to their main symptom on presentation at our outpatient clinic. A detailed medical history was recorded, paying particular attention to any allergies and reported intolerance to food. Each patient was screened for allergies; intestinal permeability tests was performed in randomly selected patients from different groups. Findings were analyzed using the chi2 test. RESULTS: Adverse reactions to one or more foods were reported by 80 patients (62.5%); skin prick tests (SPT) were positive in 67 patients (52.3%) with no significant differences between patients complaining of different symptoms. Patients who reported a food intolerance had more positive SPTs than those who did not (47 of 80 [58.7%] vs 20 of 48 [41.7%]); this difference was not statistically significant, although it suggests a trend (p < 0.0610). There was little consistency between the specific foods reported to cause intolerance and those resulting from the tests (11 of 80 patients, 13.7%). The intestinal permeability test was normal in 29 of 33 patients (87.9%). CONCLUSIONS: More than 50% of IBS patients were found sensitized to some food or inhalant without any typical clinical signs. Patients were unable to identify potentially offending foods. The lack of a correlation between SPT results and reported food allergies needs further investigation to clarify the pathophysiology and improve the diagnosis of intestinal food allergies.     

Study of food allergy in the Spanish population

BackgroundThe aim of the study was to investigate the prevalence of food allergy in patients referred to our Allergy Unit and to evaluate the diagnostic methods used.MethodsWe selected 674 patients referred to the Allergy Unit of our hospital from May 2002 to October 2004. The prevalence of symptoms was determined by a standardized questionnaire, prick-prick test, and serum specific IgE. In a second phase, double- blind oral challenge tests were administered.ResultsFood allergy was found in 106 patients (15.7%): 71 adults (67 %) and 35 children (33 %). The prevalence of food allergen sensitization was 14 % in adults and 20.8 % in children. A total of 89.6 % of the patients experienced symptoms immediately. Only 29.2% the patients of sought medical attention and adrenaline was administered to five (16.1 %). The foods most frequently involved in allergic reactions were fruits (56.6%) and tree nuts (22.6%).The most common symptoms were oral allergy syndrome (46.2 %), urticaria (32.1 %), and anaphylaxis (14.2 %).Combining the results of the questionnaire with those of prick-prick tests in patients whose allergy was confirmed by double-blind, placebo-controlled food challenge (9.1 %) showed a sensitivity of 95.5 %, a negative predictive value of 96 %, a specificity of 75 % and a positive predictive value of 73%.Conclusions1. The prevalence of food allergy in our sample was 9.1 %. 2. The foods most frequently involved in allergic reactions were fruits and tree nuts. 3. The most common symptoms were oral allergy syndrome, urticaria, and anaphylaxis. 4. Combining our questionnaire with in vivo tests allowed us to diagnose 75-96% of patients with no food allergy and 95 % of food allergy patients.     

Gastrointestinal allergy in adults

The prevalence of food allergy reaches 3% in the adult population. Chronic gastrointestinal allergy is a rare entity: 4.2% of food allergies in adults, and represents 3.2% of all intestinal disorders. Non-specific symptoms are the rule but eosinophilic gastrointestinal disorders are the subject of much interest. Endoscopy and biopsies of the gastrointestinal tract help the differential diagnoses. Food allergy is suspected from the patient's history leading to skin tests and laboratory tests identifying a sensitization but allergy is only confirmed by standardized challenges or eviction diets over a sufficiently long period. New types of investigations coupling oral challenges to foods to gastroenterological techniques should be studied further.     

Irritable bowel syndrome: is the search for lactose intolerance justified?

OBJECTIVES: To determine if confirmation of hypolactasia offers any benefit to the dietary treatment of patients with irritable bowel syndrome (IBS). METHODS: One hundred and twenty-two consecutive IBS patients (37 male, 85 female) were given lactose hydrogen breath tests (LHBT). Those with positive LHBT followed a low lactose diet for 3 weeks. Those improving on the diet were given double-blind, placebo-controlled challenges (DBPCC) with 5 g, 10 g and 15 g of lactose and a placebo, to confirm lactose intolerance. Those who did not respond to the low lactose diet followed either an exclusion or low fibre diet. Symptoms scores were kept prior to the LHBT, 8 h post-LHBT and daily whilst following any dietary change. Patients with negative LHBT returned to clinic and subsequent dietary interventions were recorded. RESULTS: LHBT was positive in 33/122 (27%) IBS patients. Syrr otom scores prior to LHBT were not significantly different between the two groups, but after LHBT the symptoms in the positive group were significantly worse. Twenty-three patients followed a low-lactose diet of which only nine (39%) improved. Six who did not improve followed an exclusion diet, three improved and all were intolerant of milk. Three tried a low fibre diet with two improving. DBPCC were inconclusive. In the negative LHBT group 35 agreed to try a diet and 24 improved (69%). Eight were intolerant of cow's milk. CONCLUSIONS: Use of a low lactose diet was disappointing in IBS patients with lactose malabsorption. Food intolerance was demonstrated in IBS patients with positive or negative LHBT and milk was identified as a problem in both groups. DBPCC were inconclusive. There appears to be little advantage in trying to separate patients who malabsorb lactose from others with IBS.     

Symptoms of food allergy

Adverse reactions to foods can be due to many causes, but only those involving an immunological mechanism can be defined as food allergic disease. An increasing number of gastrointestinal and other diseases are being shown to involve food intolerances. Immediate reactions with symptoms within hours of eating a particular food are most readily shown to be due to food allergy and are often associated with the presence of food-specific IgE as shown by skin prick tests and RASTs. When reactions are delayed for 24 to 48 hours or more, underlying food intolerance is harder to recognize and much less often shown to be due to allergy. At present, diagnosis and management depends on dietary manipulation, showing that symptoms improve on food avoidance and are reproduced by food challenge (preferably double-blind). Further understanding of the mechanisms involved in food allergy, in Crohn's disease and irritable bowel syndrome may allow the development of simple tests to identify the foods concerned and perhaps, in the case of allergic disease, cure by the induction of tolerance.     

Double blind, placebo controlled food reactions do not correlate to IgE allergy in the diagnosis of staple food related gastrointestinal symptoms.

BACKGROUND: The mechanisms for adverse reactions to foods in the gastrointestinal tract are poorly understood. There is conflicting evidence in the literature on the role for IgE mediated allergy in gastrointestinal reactions to staple foods. AIM: The aim was therefore to study the role of IgE mediated allergy in a group of patients with a history of gastrointestinal symptoms related to staple foods (cows' milk, hens' egg, wheat and rye flour) verified in double blind placebo controlled challenges (DBPCFC). PATIENTS: Fifteen patients with DBPCFC, identified by screening of 96 consecutive patients referred to our allergy clinic for investigation of suspected gastrointestinal symptoms due to staple foods. METHODS: The screening included diaries as well as elimination diets and open and blinded food challenges. The frequency of atopy were compared between the double blind positive and double blind negative patients. RESULTS: The positive DBPCFC in the 15 patients included eight patients with milk intolerance, four with wheat flour, two with egg, and one with rye flour. There was no indications of an allergic pathogenesis in all 15 patients with positive DBPCFC, as the skin prick test and radioallergosorbent test were negative for the relevant allergens. The frequency of atopy was four of 21 (19%) in the double blind negative group and three of 15 (20%) in the double blind positive group. CONCLUSION: In adult patients with staple food induced gastrointestinal symptoms, objectively verified by DBPCFC, there were no indications of IgE mediated allergy to the relevant foods suggesting other mechanisms in adults than in children. Future studies may include measures of local events in the shock organs in relation to food intake, for instance utilising inflammatory markers in jejunal fluids.     

Gastrointestinal food hypersensitivity: Symptoms, diagnosis and provocation tests.

As many as 25% of the general population in Western countries believe that they suffer from adverse reactions to food. However, the actual prevalence of food allergy is much lower. Food-induced allergic reactions cause a variety of symptoms including cutaneous, gastrointestinal and respiratory tract. Food allergy might be caused by IgE-mediated, mixed (IgE and/or non-IgE) or non-IgE-mediated (cellular) mechanisms. The clinical diagnosis is based on a careful history, laboratory findings (total and specific IgE), skin prick test, elimination diet and food challenges. New intestinal provocation tests have also been applied to pick up the allergic response of the duodenal mucosa by endosonography and external ultrasound. The management of food allergy continues to be a strict avoidance of the offending food item.     

Food Intolerances and Eosinophilic Esophagitis in Childhood

Food intolerance is an adverse reaction to a particular food or ingredient that may or may not be related to the immune system. A deficiency in digestive enzymes can also cause some types of food intolerances like lactose and gluten intolerance. Food intolerances may cause unpleasant symptoms, including nausea, bloating, abdominal pain, and diarrhea, which usually begin about half an hour after eating or drinking the food in question, but sometimes symptoms may delayed up to 48 h. There is also a strong genetic pattern to food intolerances. Intolerance reactions to food chemicals are mostly dose-related, but also some people are more sensitive than others. Diagnosis can include elimination and challenge testing. Food intolerance can be managed simply by avoiding the particular food from entering the diet. Babies or younger children with lactose intolerance can be given soy milk or hypoallergenic milk formula instead of cow’s milk. Adults may be able to tolerate small amounts of troublesome foods, so may need to experiment. Eosinophilic esophagitis (EE) is defined as isolated eosinophilic infiltration in patients with reflux-like symptoms and normal pH studies and whose symptoms are refractory to acid-inhibition therapy. Food allergy, abnormal immunologic response, and autoimmune mechanisms are suggested as possible etiological factors for EE. This article is intended to review the current literature and to present a practical approach for managing food intolerances and EE in childhood.     

Japanese Guideline for Food Allergy

Food allergy is defined as “a phenomenon in which adverse reactions (symptoms in skin, mucosal, digestive, respiratory systems, and anaphylactic reactions) are caused in living body through immunological mechanisms after intake of causative food.”Various symptoms of food allergy occur in many organs. Food allergy falls into four general clinical types; 1) neonatal and infantile gastrointestinal allergy, 2) infantile atopic dermatitis associated with food allergy, 3) immediate symptoms (urticaria, anaphylaxis, etc.), and 4) food-dependent exercise-induced anaphylaxis and oral allergy syndrome (i.e., specific forms of immediate-type food allergy).Therapy for food allergy includes treatments of and prophylactic measures against hypersensitivity like anaphylaxis. A fundamental prophylactic measure is the elimination diet. However, elimination diets should be conducted only if they are inevitable because they places a burden on patients. For this purpose, it is highly important that causative foods are accurately identified. Many means to determine the causative foods are available, including history taking, skin prick test, antigen specific IgE antibodies in blood, basophil histamine release test, elimination diet test, oral food challenge test, etc. Of these, the oral food challenge test is the most reliable. However, it should be conducted under the supervision of experienced physicians because it may cause adverse reactions such as anaphylaxis.     

Pearls and Pitfalls in Diagnosing IgE-Mediated Food Allergy

The term “food allergy” is used by many patients and clinicians to describe a range of symptoms that occur after ingestion of specific foods. However, not all symptoms occurring after food exposure are due to an allergic, or immunologic, response. It is important to properly evaluate and diagnose immunoglobulin E (IgE)-mediated food allergy as this results in reproducible, immediate onset, allergic reactions that can progress toward life-threatening anaphylaxis. Proper diagnosis requires understanding of the common foods that cause these reactions in addition to key historical elements such as symptoms, timing and duration of reaction, and risk factors that may predispose to development of IgE-mediated food allergy. Diagnostic testing for food-specific IgE can greatly aid the diagnosis. However, false-positive test results are very common and can lead to overinterpretation, misdiagnosis, and unnecessary dietary elimination. This review discusses important aspects to consider during evaluation of a patient for suspected IgE-mediated food allergy.     

食物抗原特异性IgG和IgE在功能性胃肠病发病中的作用

背景：许多功能性胃肠病患者于进食某些食物后出现症状加重。目的：测定肠易激综合征（IBS）和功能性消化不良（FD）患者的血清食物抗原特异性IgG和IgE，探讨食物过敏在功能性胃肠病发病中的作用。方法：符合罗马Ⅱ标准的37例IBS患者、28例FD患者以及20例健康志愿者纳入本研究。以酶联免疫吸附测定（ELISA）检测受试者血清中14种食物抗原特异性IgG和IgE，同时测定血清总IgE水平。通过问卷调查行症状评分，分析血清食物抗原特异性IgG水平与症状总评分的相关性。结果：与健康对照组相比，IBS组血清中螃蟹、鸡蛋、河虾、大豆和小麦抗原特异性IgG水平显著升高（P〈0．05），FD组血清中鸡蛋和大豆抗原特异性IgG水平显著升高（P〈0．05）。三组间血清总IgE水平和食物抗原特异性IgE阳性率差异无统计学意义。IBS组和FD组血清食物抗原特异性IgG水平与症状总评分之间无明显相关性。结论：IBS和FD患者血清中部分食物抗原特异性IgG水平显著升高．提示IgG介导的食物过敏可能是功能性胃肠病潜在的发病机制之一。     

Specific food intolerance: its place as a cause of gastrointestinal symptoms.

Thirteen out of 49 patients suspected of having specific food intolerance after withdrawal and reintroduction of specific foods, were further subjected to double blind placebo controlled food challenges. Only three of these subjects were thus shown to have proven specific food intolerance. Of the remaining 10, nine were strong 'placebo reactors'. The study suggests that a small number of patients with gastrointestinal symptoms have verifiable specific food intolerance but that a greater number have symptoms attributable to psychogenic causes.     

Lactose intolerance in patients with irritable bowel syndrome from northern India: a case-control study

BACKGROUND AND AIM: Symptoms of irritable bowel syndrome (IBS) and lactose intolerance (LI) overlap. Data on the frequency of LI in patients with IBS from India are scanty. The aim of this study was to evaluate: (i) the frequency of LI in patients with IBS and its various subtypes as compared with healthy subjects (HS) from northern India; (ii) the relationship between self-reported milk intolerance and laboratory evidence of LI; and (iii) the role of small intestinal bacterial overgrowth in LI in patients with IBS. METHODS: 124 patients with IBS (Rome II criteria) and 53 age- and gender-matched HS were studied for LI using the lactose hydrogen breath test (LHBT) and the lactose tolerance test (LTT). Symptoms following lactose ingestion (diarrhea, bloating or distension) during the test and history of milk intolerance were recorded. Sixty-nine of the patients with IBS also underwent a glucose hydrogen breath test (GHBT). Patients with IBS were classified into those with diarrhea (IBS-D; >3 loose stools/d), constipation predominant (IBS-C; <3 stools/week) and indeterminate (IBS-I; between >or=3/week and 相似文献   

Four-sample lactose hydrogen breath test for diagnosis of lactose malabsorption in irritable bowel syndrome patients with diarrhea

AIM: To validate 4-sample lactose hydrogen breath testing (4SLHBT) compared to standard 13-sample LHBT in the clinical setting.METHODS: Irritable bowel syndrome patients with diarrhea (IBS-D) and healthy volunteers (HVs) were enrolled and received a 10 g, 20 g, or 40 g dose lactose hydrogen breath test (LHBT) in a randomized, double-blinded, controlled trial. The lactase gene promoter region was sequenced. Breath samples and symptoms were acquired at baseline and every 15 min for 3 h (13 measurements). The detection rates of lactose malabsorption (LM) and lactose intolerance (LI) for a 4SLHBT that acquired four measurements at 0, 90, 120, and 180 min from the same data set were compared with the results of standard LHBT.RESULTS: Sixty IBS-D patients and 60 HVs were studied. The genotype in all participants was C/C-13910. LM and LI detection rates increased with lactose dose from 10 g, 20 g to 40 g in both groups (P < 0.001). 4SLHBT showed excellent diagnostic concordance with standard LHBT (97%-100%, Kappa​​ 0.815-0.942) with high sensitivity (90%-100%) and specificity (100%) at all three lactose doses in both groups.CONCLUSION: Reducing the number of measurements from 13 to 4 samples did not significantly impact on the accuracy of LHBT in health and IBS-D. 4SLHBT is a valid test for assessment of LM and LI in clinical practice.     

Prevalence of food allergy in 137 latex-allergic patients.

There have been reports of increased prevalence of certain food allergies in patients with Type I latex allergy (LA). A detailed food allergy history was obtained from 137 patients with LA. Latex allergy was defined by positive history of IgE mediated reactions to contact with latex and positive skin prick test to latex and/or positive in vitro test (AlaSTAT and/or Pharmacia CAP). Food allergy was diagnosed by a convincing history of possible IgE mediated symptoms occurring within 60 minutes of ingestion. We identified 49 potential allergic reactions to foods in 29 (21.1%) patients. Foods responsible for these reactions include banana 9 (18.3%), avocado 8 (16.3%), shellfish 6 (12.2%), fish 4 (8.1%), kiwi 6 (12.2%), tomato 3 (6.1%), watermelon, peach, carrot 2 (4.1%) each, and apple, chestnut, cherry, coconut, apricot, strawberry, loquat, one (2.0%) each. Reactions to foods included local mouth irritation, angioedema, urticaria, asthma, nausea, vomiting, diarrhea, rhinitis, or anaphylaxis. Our study confirms the earlier reports of increased prevalence of food allergies in patients with LA. We also report increased prevalence of shellfish and fish allergy not previously reported. The nature of cross reacting epitopes or independent sensitization between latex and these foods is not clear.     

Gastrointestinal food allergy: new insights into pathophysiology and clinical perspectives

Adverse reactions to food that result in gastrointestinal symptoms are common in the general population; while only a minority of such individuals will have symptoms due to immunologic reactions to foods, gastrointestinal food allergies do exist in both children and adults. These immune reactions are mediated by immunoglobulin E-dependent and -independent mechanisms involving mast cells, eosinophils, and other immune cells, but the complexity of the underlying mechanisms of pathogenesis have yet to be fully defined. Knowledge of the spectrum of adverse reactions to foods that affect the digestive system, including gastrointestinal food allergy, is essential to correctly diagnose and manage the subset of patients with immunologically mediated adverse reactions to foods. Potentially fatal reactions to food necessitate careful instruction and monitoring on the part of health care workers involved in the care of individuals at risk of anaphylaxis. New methods of diagnosis and novel strategies for treatment, including immunologic modulation and the development of hypoallergenic foods, are exciting developments in the field of food allergy.     

Role of alimentation in irritable bowel syndrome

BACKGROUND: Different food items are made responsible for irritable bowel syndrome (IBS) symptoms, but the physiopathology of IBS remains unclear. AIMS: During a meeting in Nice, France, experts of the European Working Team of the IBiS Club discussed selected data regarding the relationships between alimentation, food items (including fibers) and IBS symptoms. METHODS/RESULTS: Food allergy remains a difficult diagnosis, but medical and general history, presence of general symptoms such as skin rash, and hypersensitivity tests may help in achieving a positive diagnosis. On the other hand, food intolerance is more confusing because of the subjectivity of the relationship between ingestion of certain foods and the appearance of clinical symptoms. Different food items which are commonly implicated in adverse reactions mimicking IBS were found to be stimulants for the gut, suggesting that patients with predominant diarrhea IBS have to be carefully questioned about consumption of different kinds of food (i.e., coffee, alcohol, chewing gum, soft drinks) and not only on lactose ingestion. Gas production is discussed on the basis of retention of intestinal gas as well as on malabsorption of fermentable substrates. The role of a large amount of this kind of substrate reaching the colon is suggested as a potential mechanism of IBS-type symptoms in overeating patients. Regarding the role of fiber in IBS, the expert group concluded that fibers are not inert substances and that they could trigger pain or bloating in some IBS patients. CONCLUSION: Despite numerous reviews on this subject, it is very difficult to give general dietary advice to IBS patients, but dieteticians may have a positive role in managing such patients.     

Pediatric food allergy update

Food allergy is mostly a childhood disease that differs from the adult-onset allergy in several aspects, including the prevalence, commonly offending foods, symptomatology, and prognosis. The prevalence is much overestimated by the public, but it probably affects up to 6% of children. In some cases, the diagnosis might be clearly evident, but in most cases an expert evaluation may be needed that usually includes verification by challenge testing. Currently, the management of food allergy is avoidance of the offending foods together with the availability of pharmacologic agents for symptomatic treatment, including self-administered epinephrine. The latter is of utmost importance in highly allergic subjects because accidental trivial exposure is not uncommon. Recent studies promise immunomodulatory agents that might be of potential use for prophylaxis. One such agent is anti-immunoglobulin E, which might be available in the near future.