Food Allergy

Food Allergies

Food Allergies

Peanuts can leave you breathless. Cat dander can lead to itchy eyes, a stuffy nose, coughing and sneezing. And most of us have suffered through those seasonal allergies with horrible pollen counts. Learn more...

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Immunoglobulin EMediated Food Allergy Syndromes

Food allergies are often categorized for the organ systems they affect and by the immune mechanisms involved (Table 57-2) (Sicherer, 2002). Immune mediated reactions to food included immunoglobulin (Ig)E and sometimes IgG4-mediated responses that degranulate mast cells and Food allergy (immune-mediated mechanisms) Food intolerance (nonimmune mechanisms) basophils, so-called type I hypersensitivity. Other forms of food allergy can involve T cells, the generation of immune-complexes, and or the activation of eosinophils. Although the dermatologic and respiratory tract manifestations of food allergy are often better recognized, the GI tract can be affected by food allergies in various ways. IgE-mediated reactions to foods induce classic GI anaphylaxis in which food allergic reactions result in immediate hypersensitiv-ity within the GI tract resulting in nausea, vomiting, diarrhea, cramping, and abdominal pain. Isolated GI food allergy anaphylaxis is a relatively rare manifestation of...

Tests for the Diagnosis and Management of Food Allergy

Methods to detect food-specific IgE including prick skin testing and measurements in blood are helpful in clinical practice but standardized tests to detect non-IgE mediated food allergy are not as well developed. Skin prick testing provides a readily available and relatively inexpensive means to assess a panel of food allergens in both children and adults. The major limitation of skin testing is its poor positive predictive value (many asymptomatic patients exhibit reactions to food allergens) but a negative test in the absence of antihistamine drugs strongly suggests that immediate hypersensitivity is an unlikely mechanism for the patient's food-induced complaints. Skin testing is not helpful in predicting who might outgrow their food allergies, and, in fact, skin reactivity to foods can persist without clinical manifestations while the individual goes on to develop inhalant allergies. Although quite widely used by various practitioners, sublingual challenge or neuro-muscular...

Newer Therapies for Food Allergy Biologic Therapy

Perhaps the most exciting developments in the field of food allergy are new therapeutic approaches that modulate immune responses to foods (Nowak-Wegrzyn, 2003). These include tolerogenic peptides, recombinant epitopes, anti-IgE and DNA vaccination, as well as administration of Th1 type cytokines, such as interleukin (IL)-12 and interferon , or strategies to antagonize the actions of Th2 cytokines, such as IL-4 and Il-5. The benefit of such approaches in food allergy was recently documented in a double blind randomized, placebo controlled, dose-ranging trial, in which a humanized monoclonal IgG1 antibody against IgE that recognizes and masks an epitope in the CH3 region of IgE responsible for binding to the FcReI on mast cells and basophils was administered subcutaneously in peanut allergic subjects (Leung et al, 2003). A statistically significant improvement (subjects increased their tolerance for peanuts from an average of 1.5 peanuts to 9 peanuts at one time) was seen between the...

Prevention of Food Allergy

The optimum means to prevent the development of allergies in high risk individuals remains an area of controversy. Recommendations have been made in the United States and in Europe for infants with a strong family history of atopy at risk of developing food and other allergies and include the exclusive use of breastfeeding for at least 4 to 6 months, delayed introduction of solid foods until after 4 to 6 months of age, particularly allergenic foods such as egg, wheat, nuts, and fish, avoidance of all CMP, and if formula is needed, to use only extensively hydrolyzed or amino-acid based formulas. Partially hydrolyzed cow's milk, soy, and goat or sheep milk products are not recommended. Hypoallergenic diets have been recommended during pregnancy and with breastfeeding for atopic mothers to reduce the incidence of food allergy in their offspring. Probiotics offer another means to prevent the development of food allergy. The rationale for using probiotics in allergic diseases is that...

Pollen Food Allergy Syndrome

The oral allergy syndrome or pollen-food allergy syndrome results from various plant proteins that cross-react with certain inhalant antigens, particularly birch, ragweed, and mug-wort (Sloane and Sheffer, 2001). Exposure to the cross-reacting foods may lead to pruritis, tingling and or swelling of the tongue, lips, palate, or oropharynx, and, occasionally, to bronchospasm or more systemic reactions. Foods that cross-react with birch include raw potatoes, carrots, celery, apples, pears, hazelnuts, and kiwi. Those individuals that are allergic to ragweed may react to fresh melons and to bananas. It is important to educate patients with inhalant allergies about potential cross-reacting foods.

Latex Food Allergy Syndrome

Latex-food allergy syndrome, also referred to as the latex-fruit syndrome, is a specific form of food allergy in which food antigens cross-react with various latex antigens (Blanco, 2003). Natural rubber latex contains over 200 proteins, 10 of which bind IgE Hevea brasiliensis latex protein allergens (HEV b 1 to 10) and cross-react with a variety of food antigens including kiwi (HEV b 5), potato and tomato (HEV b 7), and avocado, chestnut, and banana (HEV b 6). In latex-sensitive individuals exposure to these foods can result in the same symptoms as if exposed to latex ranging from pruritis, eczema, oral-facial swelling, asthma, GI complaints, and anaphylaxis. A large number of studies from around the world indicate that the natural rubber latex allergy is increasing in prevalence and that the frequency of associated food allergy varies from 21 to 58 (Blanco, 2003). Worldwide, banana, avocado, chestnut and kiwi are the most common causes of food-induced symptoms associated with latex...

Treatment of Food Allergy

The cornerstone of the management of food allergy is avoidance of the offending allergen. This is particularly important in cases of peanut allergy where trace amounts of allergen can cause significant reactions. Most fatalities due to food allergy have been due to peanut allergy. Patients with food allergies should learn to read and understand labels for hidden food allergens and to recognize the potential for foods to cross-react with other antigens (eg, banana and kiwi with latex, and birch pollen with apple, carrot, and hazel nut). In North America the Food Allergy and Anaphylaxis Network (1-800-929-4040, ) is a source of valuable information for those with various types of food allergy. Similarly, it is important for celiac patients to join local celiac disease foundations and support groups that can provide valuable information used to determine sources of gluten free foods and medications. Infants with cow's milk protein allergy present a unique situation because avoidance of...

Lactose Intolerance

Globally, lactose intolerance is the most common adverse reaction to a specific food, with most cases the result of declining levels of intestinal lactase activity in later childhood and adult life, although rare congenital deficiencies can occur. Symptoms of lactase insufficiency are usually dose related and include bloating, flatulence, and diarrhea. Secondary lactase deficiency can result from viral gastroenteritis, radiation enteritis, Crohn's disease (CD), and celiac sprue. It is important from a management standpoint to understand that individuals with constitutive lactose intolerance (1) do not suffer severe and potentially life-threatening complications of ingesting lactose and (2) are able to consume naturally lactose free diary products including most cheeses and yogurts. This contrasts with cow's milk allergic individuals who may suffer anaphylactic or asthmatic reactions to dairy products and must avoid all foods containing the culprit cow's milk protein allergen, usually...

Approach to Patients Complaining of ARF

A significant component of the difficulty in managing food allergy is determining whether the patient has food allergy or another form of ARF (Table 57-3). Guidelines for the evaluation of food allergies have recently been published as a medical position statement by the American Gastroenterological Association (Sampson et al, 2001). It is essential to obtain a careful history correlating symptoms with specific foods. Most immediate hypersensitivity reactions to food include a set of symptoms that consistently occur minutes to hours after ingesting certain foods. In some individuals, other factors, such as medications or exercise, may modulate the reaction to a specific food. Specificity of the reaction does not always imply a food allergy because patients with anaphylactoid reactions or lactose intolerance report defined reactions to specific foods. However, the nature of the reaction will help differentiate lactose intolerance (gas, bloating, diarrhea) from an allergy to cow's milk...

Other Immune Mediated GI Adverse Reactions to Food

Immunity (see Table 57-2), play a role in food protein-induced enterocolitis syndromes (FPIES), such as cow's milk protein enteropathy, and also celiac disease. FPIES also known as food protein-induced enteropathies, present in infancy or early childhood and are most commonly due to cow's milk protein followed by soy protein and less commonly, egg, fish, and other food antigens (Nowak-Wegrzyn et al, 2003). Clinical manifestations include diarrhea, vomiting, anemia, bleeding, and failure to thrive. As with many other food allergies, such cases are managed by elimination of the specific food antigen until the disease resolves with age. It is common practice to switch infants with enterocolitis from a cow's milk-based formula to a soy-protein derived formula, but because over half will react to soy protein, continued problems may result from the development of soy-protein-induced enterocolitis. Hypoallergenic or elemental feeds are often necessary in such cases.

Lawrence R SchillerMD

Most patients with gastrointestinal (GI) symptoms attribute their symptoms to something they ate and want advice from the doctor about what to eat to minimize their symptoms. Symptoms after food ingestion most often are due to normal food-induced physiological changes, such as the gastrocolic reflex, or to the effects of food digestion, such as the generation of gas. They rarely are due to food allergy or to immunologic reactions to food breakdown products, such as in celiac disease. Specific problems will not be discussed further in this chapter. There are separate chapters on food allergies (Chapter 57, Gastrointestinal Food Allergy ), celiac disease (Chapter 61, Celiac Sprue and Related Problems ), and lactose intolerance (Chapter 62, Lactose Intolerance ).

Other causes of upper airways obstruction

Anaphylaxis is a potentially life-threatening immunologically mediated syndrome in which laryngeal oedema can develop over minutes often with swelling (angioneurotic oedema) of the face, mouth and tongue. Food allergies, especially nuts and drug reactions, especially contrast media and anaesthetic drugs are usual causes of this.

Management options

It is important that mothers with a previous history of severe allergic reactions are identified antenatally. Wherever possible, the previous anaesthetic record should be obtained and a plan for her care documented. Management of the known allergic case includes a general state of readiness and awareness as well as the obvious avoidance of any known allergens. Latex allergic patients may be identified from the history in most cases by asking about food allergies and skin reactions after exposure, e.g. rubber gloves, condoms, etc. If patients have had a previous severe reaction where the allergen is unknown, pretreatment with H - and H2-antagonists + steroids should be considered, although whether this should be routinely done if the allergen is known and can be avoided is controversial. Routine screening of all women by using skin or blood testing is generally not indicated, since precautions should be taken on the basis of a strong history even if testing produces negative results.

Modify Antigenic Structure

Methods to genetically or chemically modify the antigenic structures offoods to reduce their allergic potential are also being developed. For example, it is known that single amino acid substitutions in the IgE binding site of a peanut allergen can lead to the loss of binding to these epitopes. Mutated protein or peptide immunotherapies are promising but unproven strategies to induce desensitisation to food antigens. Traditional Chinese medicine (herbal) used for allergic disorders has been shown to modulate the immune response and to block anaphylaxis in a murine model of peanut allergy suggesting that such treatments may be beneficial in human food allergy. Other experimental therapies are being directed to modifying the intestinal barrier so it is less permeable to food and other types of antigens. Although all these developments hold some promise for food allergy sufferers, none are at a stage of development so as to significantly impact the current way food allergy is treated.

Differential Diagnosis

It is important to consider the differential diagnosis of patients who complain of food-associated GI complaints because the majority will not have food allergy. The major syndrome in which patients complain of adverse reactions to foods is IBS, and other functional bowel presentations. Lactose intolerance is the most common form of food intolerance worldwide and may coexist with other GI conditions as well as food allergy. A complete medical history is often helpful because most patients with a history of food allergy have a family history of atopy, and may have a personal history of other allergic conditions, such as asthma and dermatitis. A history of latex allergy should alert the practitioner to the large number of fruits that can cross-react with latex. Similarly, the oral allergy syndrome occurs in response to inhalant plant allergens, but cross-reactivity with fruit, nut, and certain vegetable antigens is common. Finally, it is well recognized that exercise and medications...

Placebo Controlled Food Challenge

Because reactions to food antigens by RAST or skin testing are neither specific nor sensitive, a double-blinded placebo-controlled food challenge (DBPCFC), in which food antigens are administered by nasogastric tube or gelatin capsules, should be performed if possible. This technique is considered the gold standard for diagnosing food allergy but is not widely available. The DBPCFC is also less reliable when assessing for delayed reactions to foods and food additives. Clinical history and the results of skin testing help guide the choice of foods to include in the oral challenge. A number of investigators have performed the GI equivalent of skin testing by injecting the GI mucosa with a panel of antigens and observing for a wheal-and-flare response by endoscopy but this form of testing has not been incorporated into routine clinical practice.

Psychological Reactions

In certain individuals, reactions to food may be psychological (Kelsay, 2003). This is a difficult type of ARF to diagnose because the mechanisms giving rise to such reactions are poorly understood. Individuals who are not confirmed to have ARF have higher rates of hypochondria, hysteria, somatization, and anxiety than those with ARF confirmed by food challenge. An individual who experienced a severe ARF may avoid the culprit food for fear of further reactions, and there is also some evidence that hypersensitiv-ity reactions to food may be triggered through central neural mechanisms so that, eventually, just the thought of ingesting the food can trigger allergic symptoms in the absence of antigen. Food allergy itself may lead to psychological distress, and studies of food allergic subjects report an altered quality of life for the individual and their family, with severe manifestations such as anaphylaxis resulting in a post-traumatic stress situation.

Secondary Lactase Deficiency

Lactase is expressed on the tip of the intestinal microvilli, and any damage to the intestinal mucosa can therefore affect the quantity of lactase enzyme. In Table 62-1, underlying causes of secondary lactase deficiency are listed. Depending on the type of mucosal injury and its treatment, lactose intolerance is temporary but may persist for months after mucosal healing has occurred. Also, bacterial overgrowth of the small intestine may lead to increased bacterial fermentation of lactose and symptoms of lactose intolerance (but not lactase deficiency).

Supplemental Reading

A racial difference in incidence lactase deficiency. A survey of milk tolerance and lactase deficiency in healthy adult males. JAMA 1966 197 968-72. Chitkara DK, Montgomery RK, Grand RJ, Buller HA. Lactose intolerance. 2003. Available at (accessed August 29,2003). Huang SS, Bayless TM. Lactose intolerance in healthy orientals. Johnson AO, Semenya JG, Buchowski MS, et al. Correlation of lactose maldigestion, lactose intolerance, and milk intolerance. Am J Clin Nutr 1993 57 399-401. National Digestive Diseases Information Clearinghouse. Lactose intolerance. Available at (accessed August 26,2003). Suarez FL, Savaiano DA, Levitt MD. A comparison of symptoms after the consumption of milk or lactose-hydrolyzed milk by people with self-reported severe lactose intolerance. N Engl J Med 1995 333 1-4.

Johanna C EscherMD PhD and Hans A BullerMD PhD

Lactose intolerance is a clinical diagnosis and consists of symptoms such as abdominal pain, cramps, nausea, bloating, acidic diarrhea and flatulence after the ingestion of lactose (Suarez et al, 1995). The symptoms can begin 30 minutes to 2 hours after eating or drinking foods containing lactose, primarily dairy products. The severity of symptoms varies depending on the amount of lactose each individual can tolerate. Lactose intake varies with age. Lactose is the primary carbohydrate in milk, accounting for almost 35 to 55 of the daily caloric intake in infants. As weaning foods are introduced, lactose intake falls and gradually approaches the levels ingested by adults. The carbohydrate intake of adults on a typical western diet is approximately 300 g, with a lactose content of 5 (Chitkara et al, 2003). Intolerance to lactose-containing foods is a common problem worldwide except in northern Europe. The prevalence is high in the population from eastern Asia (90 or more), among Native...

Infants and Young Children

In most premature infants, lactase enzyme activity is temporarily low due to the immaturity of the intestine, but a normal lactose-containing formula is well tolerated by most. In infants with symptoms of lactose intolerance, the possibility of milk protein allergy should be excluded.

Older Children and Adults

Complete restriction of lactose for a limited time (1 to 2 weeks) is sometimes useful to ascertain the specificity of the diagnosis. After this period, these patients can experiment to find a level of lactose they can tolerate. In some patients, dairy products like aged cheeses (cheddar, Swiss, Parmesan or Romano), ice cream, or yogurt are more easily accepted without symptoms, especially if taken with other food. Most people can build up their level of tolerance by gradually introducing the lactose-containing foods. In general, many will be able to enjoy dairy products if they take them in small amounts or eat other kinds of food at the same time in order to delay gastric emptying. People who have a very low tolerance of lactose need to know that lactose is often added to prepared foods, even to products labeled nondairy (Table 62-2). People with severe lactose intolerance can be even affected by lactose used as a base for more than 20 of prescription drugs (ie, birth control pills)...

GI Disorders and ARF Functional Disorders

It is human nature for patients with GI disorders to believe that something in their diet has caused their condition even in the absence of a history of food intolerance. A significant number of GI conditions are associated with ARF but food plays a causal role in only some of these disorders. For patients with GERD, nonulcer dyspepsia, IBS, and other functional conditions, nonspecific physiological reactions to food can provoke symptoms. It is generally advisable to instruct these patients to avoid foods that cause symptoms, but nondietary measures are usually also necessary to manage their complaints. However, food protein intolerance or allergy may play a role in infants with GERD symptoms. There is no generalized role for hypoallergenic diets in IBS, although a few studies report benefit from such diets (reviewed by Spanier et al, 2003) and, in some instances, instituting a rigorous diet is helpful in convincing patients that specific dietary factors are not the sole cause of...

Primary Lactase Deficiency

Congenital lactase deficiency is an extremely rare autosomal recessive disorder, described in some families in Finland. The gene for this disorder has been located on chromosome 2, in the vicinity of the lactase gene (Jarvela et al, 1998). Affected infants have diarrhea from birth, and have been reported to have hypercalcemia and nephrocalcinosis. This disorder was fatal before the development of lactose-free infant formulas. In premature infants, when born at 28 to 32 weeks gestation, lactase activity is normally low. However, most of these children (when otherwise healthy) do not have symptoms of diarrhea from lactose intolerance, because SCFAs (from bacterial fermentation of unabsorbed lactose) will be absorbed by the colonic mucosa.

Post Surgery Syndromes

Post-surgery syndromes are another fruitful area for dietary therapy. No surgical intervention on the gut is without the potential for disturbing function, and when the disturbance is severe enough to produce symptoms, careful dietary management can improve matters substantially. Conditions in which food intolerance may aggravate symptoms include postvagotomy or postgastrectomy dumping syndrome, short bowel syndrome, ileostomy diarrhea, postresection diarrhea, and ileoanal pouch dysfunction. There are separate chapters on some of those situations.

Pharmalogic Treatments Nonresponders

A minority of adult patients with celiac disease fail to respond to treatment with a gluten-free diet (Table 61-3). The most likely cause of nonresponsiveness is continued gluten ingestion, which can be voluntary or inadvertent. Other causes of nonresponsiveness are other food intolerance diseases (eg, milk, soy), pancreatic insufficiency, enteropathy-associated T-cell lymphoma, refractory sprue, and ulcerative jejunitis.

Chronic Acalculous Cholecystitis Presentation

This diagnosis is synonymous with gallbladder dyskinesia. Patients present with similar complaints as those with chronic cholecystitis however, gallstones are absent on US. Typical presenting symptoms include nausea, bloating, fatty food intolerance, vomiting, weight loss, irregular bowel habits, and fever. There is a strong female predominance approximately 80 of patients with this disease entity are female. Gallbladder dyskinesia is frequently associated with other gastrointestinal (GI) motility disorders, such as irritable bowel syndrome.

Sheila E Crowe Md Frcpc

Adverse reactions to food (ARF) are common, with up to 50 of some populations reporting ARF (Table 57-1). The majority of ARF are nonimmunologic in origin, but true food allergies are thought to affect up to 6 to 8 of children under the age of 10 years and 1 to 2 of the adult population (Sampson, 2003), a frequency which should result in most medical practitioners seeing cases of food allergy on a regular basis. The major difficulty in managing patients with food allergy lies in making a diagnosis of food allergy, particularly when the symptoms are primarily gastrointestinal (GI). Over 50 years ago Ingelfinger and colleagues (1949) wrote gastrointestinal allergy is a diagnosis frequently entertained, occasionally evaluated, and rarely established and even today this is an apt description of the problem confronting clinicians considering a diagnosis of GI food allergy. However, substantial developments have been made in our understanding of the basic biology of food allergy with...

Eosinophilic Gastroenteritis

Food allergy is thought to play a role in some cases of eosinophilic gastroenteritis, a relatively rare condition characterized by eosinophilic infiltration of the gut and, often, peripheral eosinophilia. Approximately half the patients with eosinophilic gastroenteritis have atopic features, including food allergy. Strategies to identify and eliminate food antigens should be followed as in other food allergic conditions, but often other measures, particularly corti-costeroids, are necessary to manage patients with eosinophilic gastroenteritis. Even after thorough evaluation for parasites, an empiric course of antihelminthic therapy may be given before embarking on a course of corticosteroids. Allergic eosinophilic esophagitis presents in infancy through adolescence and manifests with symptoms of gastroesophageal reflux that are often refractory

Anaphylactoid or Pseudoallergic

Anaphylactoid or pseudoallergic reactions to food result from foods that mimic the effects of mast cell degranulation but do not involve IgE antibodies. Strawberries and shellfish may cause this type of ARF. Certain food ingredients, including additives such as salicylates, benzoates, and tartrazine, induce pseudoallergic reactions. As with true food allergy, patients exhibiting such reactions should be instructed to avoid the offending food substance if identifiable. Pharmacological reactions to food or food additives represent a relatively common type of ARF, although most of these reactions cause symptoms outside of the GI tract. Histamine found in certain cheeses or in scrombroid fish, such as tuna, can cause headaches and diffuse erythema of the skin. Certain individuals develop migraine headaches to various foodstuffs, including those rich in amines. Sulfites, tartrazine and monosodium glutamate (MSG) have all been associated with asthma, and MSG can cause a characteristic...

Elimination Diets and Diet Supplements

Cluded that most research shows no credible evidence for the effectiveness of such diets in treating ADHD. He did note that such diets may be helpful for a small subset of children who have specific food allergies, but there is no evidence that children with ADHD have any greater incidence of such food allergies than children in the general population.

Patch Testing

Diagnostic tests for non-IgE-mediated food allergies include food allergy patch testing, T-cell cytokine assays, and measurements of markers of eosinophil activation. Conventional patch testing is used to diagnose contact hypersensitivity reactions involving T cells and has been applied to the evaluation of food allergy in the setting of atopic dermatitis and allergic eosinophilic esophagitis, primarily to cow's milk proteins (De Boissieu et al, 2003). Other tests may be useful in specific conditions, such as 24hour pH monitoring in eosinophilic esophagitis. Occult parasitic infections should be excluded in order to diagnose idiopathic or allergic eosinophilic syndromes and, occasionally, a course of empiric antihelminthic therapy may be indicated. Histological analysis is important in many presentations of food allergy including eosinophilic esophagitis, food protein-induced enterocolitis and proc-tocolitis, and celiac disease.

Dietary Restrictions

Dietary restrictions for food allergy associated with ana-phylaxis and celiac disease should be maintained on a long term basis, whereas such measures can be lessened in other types of food allergy that resolve with time, particularly those presenting in early childhood. At one time it was thought that unlike other food allergies, peanut allergy was not outgrown. However, there are recent studies that indicate that there may be as high as a 50 chance of outgrowing a peanut allergy. As noted above, skin testing cannot be used to predict loss of clinical reactivity because skin tests may remain positive in a child who no longer has clinical manifestations of food allergy. Instead a decline in specific IgE levels followed by a negative oral challenge provides a better index of clinical loss of reactivity to a specific food antigen. To date, there is no definite evidence that oral desensi-tization, injection immunotherapy, or similar techniques used for allergies to inhalant allergens,...

Dietary Counseling

Input from our dietitians not only serves to reinforce dietary advice we have given patients, but also gives the patients and families another source of expertise they can draw from. Generally speaking, children with active disease are placed on fiber- and residue-restricted diets. To avoid the common misperception that the patient is condemned to this diet for life, we emphasize to our patients early on that the diet can be liberalized as they improve. Lactose intolerance is another issue and is fairly common in children with CD and is included in discussions with our patients. The ethnic distribution of lactose intolerance and management in children, and adults, is discussed in a separate chapter (see Chaper 62, Lactose Intolerance ). The main emphasis in children is to insure adequate nutrition for growth.

Carbohydrates

There is a separate chapter on lactose intolerance (see Chapter 62, Lactose Intolerance ). The most common carbohydrate that is malabsorbed is lactose or milk sugar (Vesa et al, 2000). Lactose is the primary carbohydrate in milk, and all mammals depend on lactase activity in the intestine to digest and absorb this substrate in infancy. Most mammals retain lactase activity until weaning and then turn off production of this enzyme, because milk is no longer a part of the diet. Most human populations retain lactase expression through adolescence and then become lactase insufficient. In some populations (particularly the individuals in the Northern European gene pool), lactase activity is maintained into adulthood, but is typically lost gradually, producing some degree of lactose intolerance with aging. The degree of lactose intolerance is highly variable and the development of symptoms depends not only on the amount consumed (eg, 12.5 g per glass of milk), but also on such factors as the...

Role of Stress

Various physical stresses can bring about the symptoms. Sometimes a real intestinal illness provokes the onset of the condition by the family's excessive response. Examples of this would be following a viral infection of the GI tract with the development of transient lactose intolerance, or development of fecal retention following a period of diarrhea, leading to a chronic functional disorder. Psychosocial stresses that may induce the development of recurrent abdominal pain include anxiety, problems at school, and a general preoccupation with illness. Several studies have documented that functional GI disorders may be associated with both upper and lower GI manometric abnormalities and altered intestinal transit. Recurrent abdominal pain may result from dysfunction of the autonomic nervous system, which serves as an important participant in homeostasis of the intestinal tract and modulates the sensory and motor responses to various internal

Outcome

No prospective studies have been performed on the outcome of functional abdominal pain. Once diagnosed, gastroen-terologists rarely identify an occult organic disorder. Many patients become asymptomatic within 2 to 6 weeks of diagnosis. Most children and parents accept the reassurance that the pain is not organic and that environmental modification is effective treatment. However, 30 to 50 of children may continue to have such problems into adult life, many of them developing IBS. Factors that may lead to a good prognosis for resolution of the pain include the following (1) no family history of pain, (2) being female, (3) age of onset 6 years of age, and (4) duration of symptoms 6 months. Non-ulcer dyspepsia and IBS are two variants of chronic recurrent abdominal pain, usually occurring in patients 10 years old. Some of the patients have both. Physical examination in these patients is normal. Similar to those with recurrent abdominal pain, they sleep well and are not awakened by pain....

Treatment Strategies

Calcium and vitamin D supplements should be thought of as adjunctive to the above therapies but should never be thought of as sufficiently effective to treat osteoporosis or prevent glucocorticoid-induced osteoporosis (Bernstein et al, 1996). Patients should take approximately 2 g of calcium per day. Calcium citrate supplements may be better absorbed than calcium carbonate. Dairy products are an important source of calcium. Many patients with GI diseases have been told they are lactose intolerant without sufficient data to support it. Genetic testing for lactase nonpersistence and lactose breath hydrogen testing for secondary lactose intolerance may be useful to document lactose malabsorption.

Medical Management

Even patients with anatomic or physiologic abnormalities may benefit from maximizing medical therapy. Dietary counseling regarding diarrhea-producing foods, food intolerance, and fiber intake is virtually risk-free and may ameliorate symptoms during the workup process. We counsel most patients to maximize dietary fiber intake, including use of a bulking agent. The goal is eventual intake of 25 to 30 g of fiber daily most patients start at levels substantially lower than this, and they should be counseled to increase their intake gradually to avoid excessive gassiness.

Safe Foods

Etables, fruits, and plain peanut butter. Although dairy products and cheeses are allowed, patients should be aware that the coat of certain cheeses may contain gluten. Also acquired live lactase levels are common in active celiac disease leading to lactose intolerance. Rice can be ingested in all its varieties including white rice, brown rice, rice bran, rice polish, sweet rice, and wild rice. Rice is the basis of many safe cereals and pastas. Different rice flours are often used in gluten-free baking and are usually combined with other gluten-free flours or baking ingredients. Also, acquired live lactase levels are common in active celiac disease leading to lactose intolerance.