Infants and Children

Milk and soy allergies are particularly common in infants and children. These allergies sometimes do not involve hives and asthma, but rather lead to colic, and perhaps blood in the stool or poor growth. Infants and children are thought to be particularly susceptible to this allergic syndrome because of the immaturity of their immune and digestive systems. Milk or soy allergies in infants can develop within days to months of birth. Sometimes there is a family history of allergies or feeding problems. The clinical picture is one of a very unhappy colicky child who may not sleep well at night. The diagnosis is based in part on changing the child's diet. Rarely, food challenge is used.

If the baby is on cow's milk, the doctor may suggest a change to soy formula or exclusive breast milk, if possible. If soy formula causes an allergic reaction, parents should try feeding the baby with elemental formulas, which are processed proteins (basically sugars and amino acids). There are few if any allergens within these materials. Corticosteroids are also sometimes used to treat infants with severe food allergies. Fortunately, time usually heals this particular gastrointestinal disease. It tends to resolve within the first few years of life.

Exclusive breast feeding (excluding all other foods) of infants for the first 6 to 12 months of life is often suggested to avoid milk or soy allergies from developing within that time frame. Such breast feeding often allows parents to avoid infant-feeding problems, especially if the parents are allergic (and the infant therefore is likely to be allergic). There are some children who are sensitive to a certain food, however, that if the food is eaten by the mother, sufficient quantities enter the breast milk to cause a food reaction in the child. Mothers sometimes must themselves avoid eating those foods to which the baby is allergic.

There is no conclusive evidence that breast feeding prevents the development of allergies later in life. It does, however, delay the onset of food allergies by delaying the infant's exposure to those foods that can prompt allergies and may avoid altogether those feeding problems seen in infants. By delaying the introduction of solid foods until the infant is 6 months old or older, parents can also prolong the child's allergy-free period.

Controversial Issues

There are several disorders thought by some to be caused by food allergies, but the evidence is currently insufficient or contrary to such claims. It is controversial, for example, whether migraine headaches can be caused by food allergies. There are studies showing that people who are prone to migraines can have their headaches brought on by histamines and other substances in foods. The more difficult issue is whether food allergies actually cause migraines in such people. There is virtually no evidence that rheumatoid arthritis or osteoarthritis can be made worse by foods, despite claims to the contrary. There is also no evidence that food allergies can cause a disorder called the allergic tension fatigue syndrome, in which people are tired, nervous, and may have problems concentrating, or have headaches.

Cerebral allergy is a term that has been applied to people who have trouble concentrating and have headaches, as well as other complaints. This is sometimes attributed to mast cells degranulating in the brain, but no other place in the body. There is no evidence that such a scenario can happen, and cerebral allergy is not currently recognized by allergists.

Another controversial topic is environmental illness. In a seemingly pristine environment, some people have many non-specific complaints such as problems concentrating or depression. Sometimes this is attributed to small amounts of allergens or toxins in the environment. There is no evidence that such problems are due to food allergies.

Some people believe hyperactivity in children is caused by food allergies. But this behavioral disorder has only been suggested to be associated with food additives occasionally in children, and then only when such additives are consumed in large amounts. There is no evidence that a true food allergy can affect a child's activity except for the proviso that if a child itches and sneezes and wheezes a lot, the child may be miserable and therefore more difficult to control. Also, children who are on anti-allergy medicines that can cause drowsiness may get sleepy in school or at home.

Controversial Diagnostic Techniques

Just as there are controversial food allergy syndromes and treatments there are also controversial ways of diagnosing food allergies. One of these is cytotoxicity testing, in which food allergen is added to a patient's blood sample. A technician then examines the sample under the microscope to see if white cells in the blood "die." This technique has been evaluated in a number of studies and has not been found to effectively diagnose food allergy.

Another controversial approach is called sublingual or, if it is injected under the skin, subcutaneous provocative challenge. In this procedure, dilute food allergen is administered under the tongue of the person who may feel that his or her arthritis, for instance, is due to foods. The technician then asks the patient if the food allergen has aggravated the arthritis symptoms. In clinical studies, this procedure has not been shown to effectively diagnose food allergies.

An immune complex assay is sometimes done on patients suspected of having food allergies to see if there are complexes of certain antibodies bound to the food allergen in the bloodstream. It is said that these immune complexes correlate with food allergies. But the formation of such immune complexes is a normal offshoot of food digestion and everyone, if tested with a sensitive enough measurement, has them. To date, no one has conclusively shown that this test correlates with allergies to foods.

Another test is the IgG subclass assay, which looks specifically for certain kinds of IgG antibody. Again, there is no evidence that this diagnoses food allergy.

Controversial Treatments

Controversial treatments include putting a dilute solution of a particular food under the tongue about a half hour before the patient eats that food. This is an attempt to "neutralize" the subsequent exposure to the food that the patient believes is harmful. As the results of a well conducted clinical study show, this procedure is not effective in preventing an allergic reaction.

Summary

Food allergies are caused by immunologic reactions to foods. There actually are several discrete diseases under this category and a number of foods that can cause these problems.

A medical evaluation after one suspects a food allergy is the key to proper management. Treatment is basically avoidance of the other food(s) after they are identified. People with food allergies should become knowledgeable about allergies and how they are treated and should work with their physicians.

The National Institutes of Health supports research on food allergies through grants that it provides to research institutions throughout the world. Understanding the cause of an immune system dysfunction in allergy will ultimately lead to better methods of diagnosing, treating and preventing allergic diseases.

Questions and Answers

Q. Would you discuss what common substances are in both peanuts and other kinds of nuts? The response I often get when I tell people that I am severely allergic to both peanuts and nuts is that I cannot be because peanuts are legume, unlike nuts.

A. First of all, it is possible to be allergic to two distinct foods. It is interesting that both peanuts and nuts are concentrated sources of protein, which is probably one reason why reactions to both these foods are so frequent. But you can have cross reactions between tree nuts and peanuts, or you could develop allergies to both.

Q. I would like to ask about diet during pregnancy. I have heard some talk about avoiding certain foods during your last trimester.

A. There is no evidence that avoidance of foods in the last trimester can prevent food allergies. In fact, some experimental evidence suggest this is harmful.

Q. Would gross swelling of the lips be indicative of a food allergy?

A. Well, it can be, but you can also have something called idiopathic angioedema, which can cause swelling of the lips. This disorder is not caused by food allergies. If you have such a problem, talk it over with your doctor. If there is any chance that it might be a food allergy, the doctor can place you on an elemental diet for 10 days. If the problem does not go away, you have ruled out food allergy.

Q. Is intolerance a disease entity?

A. Food intolerance is not a distinct entity. It is a term used to cover any adverse reaction to a food that doesn't have an immunologic basis.

Q. I have a 14-year old daughter who has developed chronic hives in the past nine months. She has swelling and hives on the bottom of her feet to the point where she cannot walk; her fingers swell and she cannot write. She has been skin tested for food allergies, and it was negative. We are going through the elimination diet process now and seeing some improvement, but not a whole lot. The only thing that controls it is prednisone. What would you suggest as the next step?

A. Sometimes there is a non-specific improvement as you manipulate the diet. But chronic hives and angioedema, especially of that duration, are almost never due to food allergies. Unfortunately, no cause is usually found. There is hope that they will resolve with time. I'd advise you to limit the use of steroids because steroids can do more damage than if you just use antihistamines.

Q. Is there any hope of better management of lactose intolerance than chewing tablets that help dissolve lactose during the meal?

A. Probably not, other than avoidance of foods that have lactose.

Q. What is the best way to diagnose lactose deficiency?

A. There are a couple of test that involve ingesting a specific amount of lactose and then measuring the body's response. Such blood tests are done by physicians.

Q. Can you tell us anything about gluten intolerance?

A. Gluten intolerance is associated with the disease called gluten-sensitive enteropathy or celiac disease. It is due to an abnormal immune response to gluten, which is a component of wheat and some other grains.

Q. Is it possible that many people who were given the diagnosis of irritable bowel syndrome in the past are turning out to actually have allergies?

A. There is no good evidence that irritable bowel syndrome is due to food allergies in most instances.

Q. This summer I had lunch at a fast food restaurant for the first time and I broke out in hives. The doctor seemed to think maybe it was the sulfites in the food. Now you said there had been regulations for salad bars and sulfites, but in the whole food industry are there regulations for the use of sulfites?

A. Yes, there are industry-wide regulations covering the use of sulfites. Now I do not know anything about the restaurant you ate at, but it is more likely that you ate something else you are allergic to because sulfites rarely cause hives.