Allergic (IgE) antibodies are the anti­bodies responsible for atopic allergic reactions. Minute quantities of IgE antibodies can be detected in almost everyone, but high concen­trations are usually found in atopic patients with allergic asthma or hay fever. The tendency to produce allergic antibodies in response to common environmental substances, or allergens, is characteristic of atopic patients. Such responses are currently believed to be under genetic control. See also Antibodies.

Even if one or more of the symptoms associated with food allergy is present, a food allergy may not be responsible. The same symptoms may be caused by food spoilage or contamination, by the method of cooking or feeding, by the body’s lack of an enzyme or some other digestive factor, or simply by digestive intolerance. Other causes are internal diseases involving the stomach, gall bladder, intestines, and pancreas, as well as fatigue, stress, drugs, and emotional problems. Once these possibilities have been ruled out, the food allergy patient is ready for a rigorous diagnostic process, the first step of which is a careful history. This may be followed by skin testing. Unfortunately, however, although such tests are reliable in diagnosing allergies to dust, pollen, or pets, they are less so in diagnosing the specific cause of a food allergy. Test extracts made from food tend to lose their potency fairly quickly; they often fail to provoke a skin reaction in case of proven sensitivity. Though the tests may be positive in people experiencing immediate reactions to allergenic foods, they are considered, in many cases, to be without clinical significance. Skin tests are even less reliable among patients experiencing the 1 delayed type of reaction, as the test extract contains only the whole food and no digested material—though the latter is usually involved in this kind of reaction. Another testing method involves placing diluted food extracts under the tongue, but this method is also considered unreliable and is often omitted. Treatment by administering extract solutions j under the tongue is also not a warranted method. A trial diet is the most effective procedure known for determining the specific food or foods to which a patient is allergic. On the first day, the patient eats the suspected offending food in all forms and in substantial quantities, provoking an allergic response. Then, for the next five days, the suspected offending food is avoided totally, which should result in an absence of symptoms. On day seven, the suspected offending food is again eaten, on an empty stomach, and in its pure form (that is, for example, a glass of milk, but not cheese or ice cream). The pattern of reaction and nonreaction will either be significant enough to eliminate all doubt about the effect of the food or the suspected food will be eliminated from consideration as the cause of the allergic reaction. What testing methods are used when the patient has no idea what food he or she is allergic to? Two general procedures are resorted to in this case : 1. Symptoms that occur only once in a while may be caused by infrequently eaten foods. A food allergy patient can sometimes help to determine the offending food by keeping a "food diary" in which each food eaten, the time of day, and any symptoms noted, are set down. Any medicines taken orally and any known exposure to environmental pollutants must also be recorded. A sample food diary is reproduced below. To determine the offending food, those foods that are believed to produce symptoms are checked individually by eliminating them from the diet for a week and then eating them in substantial amounts. 2. When symptoms occur every day, a special elimination diet, including at first only foods seldom found to cause allergy, may be prescribed. One by one, suspect foods are then added to the diet. When the symptoms occur regularly after a specific food is eaten, that food must be eliminated from the patient’s diet.

Histamine is a chemical released in the body by the inter­action of an allergen and an antibody; it is believed to cause the swelling and itching that accompany allergic skin disorders and the symptoms of allergic rhinitis.

Food allergy symptoms can involve specific organs and systems! of the body and sometimes every organ and system. In the respira tory system, food allergy can cause asthma (manifested by coughing and wheezing) and such nasal symptoms as itching, runny nose, sneezing, snorting, and phlegm in the throat. Diarrhea, nausea, о r vomiting, and bellyache or cramps (colic in infants) may develop when food allergy affects the digestive system. Any area of the body may be subjected to swelling (edema), in- eluding the eyes, lips, face, and tongue. If the swelling develops in the throat and upper windpipe, breathing can be seriously impaired and suffocation may result. Eczema, a chronic skin disease, can some times also be caused by food allergy, and a rash may form in the bends of the arms and possibly all over the body. Food allergy can also cause fluid to develop behind the eardrums, which may result in intermittent deafness. Other symptoms sometimes caused by food allergy are migraine headaches, a mottled tongue, and canker sores in the mouth. It has been suggested, although not yet proved, that hyperactivity, irritability, and aggressiveness in chil dren may also result from food allergy. Immediate reactions to food affecting the throat and respiratory passages are particularly dangerous. Patients experiencing shock in response to an allergenic food usually develop severe nausea, vomit­ing, hives, and swellings all over the body and may collapse. These

See Asthma, Extrinsic.

The Hymenoptera group of insects consists of yellow jackets, bees, wasps, and hornets. Stings from these insects produce dramatic, sometimes life-threatening, reactions in some people. To prevent these reactions, susceptible patients have for years been instructed to carry Adrenalin or antihistamines for immediate use when they are stung. Susceptible people have for some time also taken allergy immunotherapy injections of whole-body extract to obtain protection from future stings. In recent years, research has demonstrated that venom itself, rather than whole-body extract, is most beneficial for immuno therapy; and venom skin tests can now be given to high-risk individ­uals. Those identified as being at high risk can be treated using venom injection therapy, which appears to confer blocking antibody and probably changes mast-cell sensitivity, so that people are less likely to have an adverse reaction if stung again. Although research has led to improved therapy for stinging insect allergy, important questions remain to be answered. Are some people truly protected after the first sting, so that subsequent stings will be harmless even though the initial sting had serious consequences? What is the optimum period for immunotherapy? Can physicians assess a person’s clinical response in any way besides another sting?

Gluten is the elastic rubbery protein that binds the dough in such foods as bread, biscuits, cakes, and pastry. Allergy to gluten requires avoidance of wheat and rye, possibly barley and oats, as well as of all gluten-containing foods. The last group includes flour, wheat flour, gluten flour, graham flour, cracked wheat flour, enriched flour, malt, malt syrup, oatmeal, oats, rye, rye flour, barley, barley flour, mono-sodium glutamate (MSG), hydrolyzed vegetable protein (HVP), durum flour, dried peas or beans, and millet. Wheat starch is the traditional substitute for gluten-free baking, but it is not totally gluten-free. If this is tolerated, Aproten Pasta made by Henkel Corporation can be used as a pasta substitute. Sago, tapioca, rice, potato, soya, corn, arrowroot, buckwheat, and soft wheat (cake and pastry flour) are additional cooking substitutes. Ener-G-Foods’ Rice Bread and Nutine (gluten- and wheat-free) are two ready-made gluten-free breads. If you make your own bread, try using a combination of several allowed flours. (See the baking tips given below in this chapter.) The following flour-and-meal combination can be used as a sub­stitute in gluten-free diets. It requires at least five or six sittings and long, slow baking: 1 cup corn flour 1 cup soy flour and 3/4 cup potato 3/4 cup coarse corn meal flour 1 scant cup of fine corn meal 5/8 cup potato flour (sometimes 7/8 cup rice flour called potato starch) 5/8 cup rice flour and Уз cup 1 scant cup wheat starch potato flour The following gluten-free flour mix should be thoroughly blende and can be used in any recipe calling for all-purpose flo ur except for bread, gingerbread, doughnuts, fritters, and shortbread. It also requires at least five or six sittings and long, slow baking: 2 cups wheat starch 1 cup rice flour 3/4 cup corn flour 6 tablespoons arrowroot flour 3/4 cup potato flour 6 tablespoons tapioca flour 1/4 cup soya flour What about corn allergy and corn-free diets? If you are allergic to corn, you must avoid eating and sometimes even smelling corn and all corn-related products. Some items to be avoided are: cornflakes, baking powder, corn oil, corn syrup, corn flour, corn sugar, fritters, cerelose, sorbitol, dyno, cartose, cornstarch, chewing gum, soya milk, powdered sugar, caramel coloring, dextrose, white vinegar, commercially canned jam and preserves, fruit canned in syrup, some substitute egg yolks, and aspirin and other tablets. You should also beware of such adhesive gums as those on stamps, envelopes, and tapes, since they contain small quantities of corn. Any medication with gluconate contains corn. Cornstarch can be replaced by Featherweight cornstarch. You can also make your own corn-free baking powder by substituting the j following mixture in any recipe: 1 part baking soda 1 part potato starch 1 part cream of tartar Or you can pulverize and mix the following: 1 ounce cream of tartar 1/2 ounce tartaric acid 5 ounces bicarbonate of soda 4 ounces flour For heavy batters such as Christmas cake, try using equal amounts of cream of tartar and baking soda. What are some simple baking hints that come in handy when one is baking allergy-free recipes? Although you may think otherwise, allergy-free baking is not very different from your regular baking methods. The following informa­tion will help guide you. Heavier flour and yeast-free baked products have a heavier texture, and their taste depends on your choice of flour. If you use dark-colored baking pans, especially the black-finish kind, turn the oven temperature 25 degrees F lower than the recipe calls for. When baking cookies, set your timer for two or three minutes less than the time the recipe calls for. Your cookie sheets and your oven influence baking time. Watch the bottom sheet carefully when baking two sheets at a time. When using dark-finish pans for breads and cakes, set the timer for as much as ten minutes less than the time indicated on the recipe and check the progress frequently, without opening the oven door. For future reference, mark the appropriate time on the recipe. The weather is another important factor in baking results. Since flours can lose moisture in the winter, some recipes may require the addition of liquid. If the dough is too soft to handle, add more flour. Sifting is not necessary before measuring. After combining the dry ingredients, however, sifting will ensure that the ingredients do not ball during mixing. If you are using a food processor, sifting is not necessary, since balling doesn’t affect the final outcome, but do stir the flour before measuring. (The baking tips in this answer courtesy of Carol Rudoff, President, American Allergy Association, and Editor, Living with Allergies.)

Abbreviated ABPA, this is an unusual lung disease found in allergic asthmatics and caused by an allergic reaction to a fungus growing in the bronchial tubes. Patients with this form of asthma characteristically have episodes of patchy pneumonia in their lungs and high levels of IgE and eosinophils. See also Aspergillus.

What about treatment in the future? What techniques do scientists use to develop new methods of treatment? How can they be certain of the safety of a treatment for humans? What are the requirements of proper research? What constraints are placed on research, con­straints that sometimes delay the marketing of new drugs? All these questions are relevant to allergy research. Both patients and physicians needs to be better informed about this research, which involves population studies, laboratory studies, experiments using animals, and finally, testing in humans.

Spores are the reproductive cells of certain plants and or­ganisms. Inhaled fungal spores are frequently the cause of allergic symptoms such as rhinitis and asthma. See also allergens; fungi; molds.