Dairy Allergies

Definition

Food allergy or hypersensitivity refers to an abnormal immunologic reaction in which the body's immune system produces an allergic antibody, called immunoglobulin E (IgE) antibody, to usually harmless foods, such as milk or egg protein, resulting in allergy symptoms such as wheezing, diarrhea or vomiting.

Description

Food allergy is different from food intolerance. The term "food allergy" is sometimes used in a vague, all-encompassing way, muddying the waters for people who want to understand what a real food allergy is.

True food allergies are serious and, in rare cases, can be fatal. Intolerance to milk and other foods is much more common and usually less serious than allergy. Food intolerances may produce symptoms similar to food allergies, such as abdominal cramping. But while people with true food allergies must avoid certain offending foods altogether, people with food intolerance can often eat small amounts of the offending food without experiencing symptoms.

Lactose intolerance is sometimes mistaken for milk allergy. Lactose intolerance is a condition in which a person lacks the enzyme to break down the sugar found in milk for proper digestion. This results in bloating, abdominal discomfort and diarrhea.

Estimates are that up to 80 percent of African-Americans have lactose intolerance, as do many people of Mediterranean or Hispanic origin. It is quite different from the true allergic reaction that some people may have to the proteins in milk.

Food allergens, those parts of foods that cause allergic reactions, are usually proteins. Most of these allergens can still cause reactions even after they are cooked or have been digested in the intestines. Numerous food proteins have been studied to establish allergen content.

Recent studies indicate that the protein in cow's milk is one of the most common food allergens. The protein of cow's milk is composed of two types: casein (80 percent) and whey (20 percent). Since most of these allergens are heat resistant, scalding or boiling the milk will not help in most cases. People who must avoid milk because of allergies should be sure to get adequate calcium and vitamin D in their diets.

Egg allergy can be quite dangerous in children. It is the white, not the yolk, that causes the problem, and raw white is more likely than cooked to provoke symptoms. But even cooked whites may be potent allergens, and an egg-sensitive person may have to avoid the yolks, since they can be contaminated with whites.

Symptoms

Milk allergy can be manifested as asthma, eczema (an itchy rash), rhinitis (inflamed nose), and gastrointestinal distress, as well as bleeding, pneumonia, and even anaphylaxis (shock). Every parent should be alert for signs of milk allergy.

Danger Of Anaphylaxis

The greatest danger in food allergy comes from anaphylaxis, a violent allergic reaction involving a number of parts of the body simultaneously. Anaphylaxis usually occurs after a person is exposed to an allergen to which he or she was sensitized by previous exposure (that is, it does not usually occur the first time a person eats a particular food).

Although any food can trigger anaphylaxis (also known as anaphylactic shock), peanuts, tree nuts, shellfish, milk, eggs, and fish are the most common culprits. As little as one-fifth to one-five-thousandth of a teaspoon of the offending food has caused death.

Anaphylaxis can produce severe symptoms in as little as 5 to 15 minutes, although life-threatening reactions may progress over hours. Signs of a reaction include difficulty breathing, feeling of impending doom, swelling of the mouth and throat, drop in blood pressure, and loss of consciousness.

The sooner anaphylaxis is treated, the greater the person's chance of surviving. The person should be taken to a hospital emergency room, even if symptoms seem to subside on their own.

Experts advise people who are susceptible to anaphylaxis to carry medication, such as injectable epinephrine, with them at all times and to check the medicine's expiration date regularly.

Diagnosis

Keeping a food diary may be helpful. The most common way to test for food allergies is with an "elimination diet," in which all common allergy-causing foods are eliminated over a few weeks until symptoms lessen. The foods are then re-introduced to see which cause the symptoms to return.

An elimination diet should not be undertaken without very specific guidance and supervision from a doctor.

Treatment

The basic principles of treating food allergy are (1) avoidance of the allergen, and (2) symptomatic therapy.

Avoidance of specific foods is critical once a true food allergy has been diagnosed by your physician. Soy-based formulas are available for infants with milk allergy. Patients allergic to milk must be extra vigilant because processed food may contain milk products labeled as "natural flavorings" or "seasonings."

Your physician may recommend certain medications to control allergic symptoms.

Questions to Ask Your Doctor

Is my illness an allergy to dairy products?

Can an allergy test be performed to pinpoint the source of the allergens?

Do you recommend an "elimination diet" to identify the source of the allergies?

Which foods should be avoided?

What can be done to cope with the symptoms?