World Digestive Health Day WDHD – May 29, 2016 FOOD ALLERGY AND THE DIGESTIVE TRACT, continued Table 1: Cross-reactivity between pollens and fruits and vegetables in oral allergy syndrome.2 Birch Almond, aniseed, apple, apricot, carrot, celery, cherry, hazelnut, parsley peach, peanut, pear, and plum Ragweed Banana, cantaloupe, cucumber, honeydew, watermelon and zucchini Mugwort Aniseed, bell pepper, broccoli, cabbage, caraway, cauliflower, celery, fennel, garlic, mustard, onion, and parsley Orchard Cantaloupe, honeydew, peanut, tomato, watermelon, and white potato Timothy Swiss chard and orange Symptoms of the oral allergy syndrome—also called pollenfood allergy syndrome, which is a form of contact hypersensitivity almost entirely confined within the oropharynx—include the rapid onset of pruritus and swelling of the lips, tongue, palate, and throat.7. These symptoms usually resolve within minutes of onset, however. Individuals who have seasonal allergic rhinitis to birch or ragweed pollens commonly show signs of oral allergy syndrome after eating raw fruits and vegetables (see Table 1). Eosinophilic esophagitis (EoE) is a new disease, not reported until very late in the past century. It presents with dysphagia, food impaction, heartburn, and regurgitation. It occurs more often in males and is often associated with other atopic disorders. Endoscopic findings include edema, concentric fixed rings, exudates, linear furrows (as demonstrated in Figure 2), and in advanced disease, strictures. Currently, there are no established markers that aid in determining which foods are the culprits other than eliminating common foods (6-food diet or 4-food diet) to observe if there is clinical and endoscopic improvement, as well as reduced numbers of eosinophils in mucosal samples. After a response to food elimination, one food group at a time is reintroduced to assess clinical, endoscopic, and histological endpoints. If there is no worsening of esophageal mucosal eosinophil counts another food group is introduced and so on, until there is worsening of symptoms, endoscopy, and pathology. Eventually through repeated periods of avoidance and challenges a specific exclusion diet can be established for an individual patient. In general, wheat and milk should be the last group to test as they are the most likely to produce a recrudescence of EoE. Additional therapies include proton pump inhibitors (PPIs) to treat co-existing acid reflux and/or PPI-responsive EoE, topical corticosteroids (swallowed fluticasone or oral budesonide suspension), and rarely systemic corticosteroids. Oral prednisone and budesonide capsules are usually used for treating eosinophilic gastroenteritis (EGE). EGE is less associated with food-allergy and food elimination has little benefit compared to EoE. Interestingly, while EoE prevalence is increasing, the frequency of EGE has not changed since the mid-1950s. FOOD ALLERGY AND THE GLOBAL PERSPECTIVE More than 50 million Americans are estimated to have allergies and up to 15 million of them have food allergies.8 One in every 13 children under the age of 18 years have food allergy. US healthcare dollars spent on food allergy approaches $25 billion per year. Although the vast majority of ARFs, more than 85%, are not due to true food allergies. One-fifth of the US population self-imposes diet modifications because of perceived ARFs.2 Most ARFs are due to food intolerances that, though often unexplained, do not involve the immune system. Food allergies affect 4% of adults and 8% of children in the USA and the prevalence seems to be on the rise.8 The U.S. Centers for Disease Control and Prevention (CDC) reported a 50% increase in food allergy between 1997 and 2011. Approximately 200,000 emergency room visits and 300,000 ambulatory-care visits annually in the United States are related to food allergy.2 Eight foods account for 90% of all Figure 2. 26 WGO Handbook on DIET AND THE GUT World Digestive Health Day WDHD May 29, 2016
WGO Handbook on Diet and the Gut_2016_Final
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