All allergies, whether caused by food, inhaled substances or substances that come in contact with the skin, are the result of an immune system reaction similar to an attack against a bacterium or virus. About 90 percent of children's food allergies are triggered by milk, eggs, peanuts, wheat or soy products. Other common food allergy triggers are nuts, fish and shellfish. Less than five percent of infants and children have food allergies. Allergy to eggs or milk is often outgrown by the third year of life.
WHAT HAPPENS DURING AN ALLERGIC REACTION TO FOOD?
Food may trigger classic allergic responses such as hives (large, itchy, red bumps on the skin), rashes and respiratory problems. In the worst cases, they may cause severe swelling in the throat and a rapid drop in blood pressure, a pattern known as anaphylaxis. Some people with food allergies develop mainly gastrointestinal symptoms, which may include nausea, vomiting, diarrhea, gas and bloating.
Sometimes, a more mild reaction known as food intolerance is mistaken for a food allergy. A food intolerance produces digestive symptoms similar to those caused by some food allergies, but intolerance is a result of direct effects of food components, rather than an immune system response. The most common food intolerance is lactose intolerance, an inborn inability to digest the sugar in milk. Another recently recognized food intolerance is to a sweet substance called sorbitol that is abundant in pear, cherry and prune juices and some candies. Sorbitol intolerance can cause chronic diarrhea, gas and abdominal pain, particularly in children who drink several cups of juice a day.
WHAT CAUSES FOOD ALLERGIES?
In an allergy, a substance perceived as a threat (usually a specific antigen found in a particular food) binds to the IgE type of antibody (a protein produced by the white blood cells). IgE in turn binds to cells called mast cells. The clinging IgE complex causes the mast cells to release several chemicals called histamines. (These are the chemicals that antihistamine drugs fight.) Histamine exerts powerful effects on the body. When it penetrates the skin, fiery red welts rise up. Elsewhere, histamine stuffs up the nose and brings tears to the eyes. In rare cases, histamine release can cause anaphylactic shock.
IS MEDICAL ATTENTION NECESSARY?
Yes, particularly if a child has a severe reaction to a food. Reactions with widespread redness of the skin, hives, wheezing, hoarseness, low blood pressure, or severe vomiting or diarrhea may be quite dangerous. If there is any doubt at all about which is the offending food, the pediatrician may refer you for evaluation to an allergist who may do limited skin testing to help identify which foods in a meal caused the symptoms. Sometimes the suspect food needs to be fed in the office to confirm sensitivity. Feeding of suspect foods at home is to be avoided because of the possibility of provoking a severe reaction.
WHAT TREATMENTS ARE AVAILABLE?
The primary treatment for food allergies is simply to avoid the responsible foods, but this can be difficult, particularly if you eat in restaurants or purchase packaged food.
Parents of children who have had severe reactions (anaphylactic shock) should ask the pediatrician about injection devices for epinephrine (Adrenalin). This is the first-line drug for such reactions. Children with severe reactions should also have a Medic-Alert tag to identify their problem in the absence of parents. Children who only have very mild reactions may benefit from oral antihistamines when they are accidently exposed to the food.
CARING FOR THE CHILD WITH FOOD ALLERGIES
• Be certain to alert the day care provider or preschool teacher of the child's allergy.
• Teach the child which foods to avoid.
• Be sure that the child knows never to eat food from someone else's lunch box.
• Consider having the child wear a medical necklace or bracelet warning of the allergy, especially if there is a history of severe symptoms.
• Ask your doctor if any over-the-counter medications can be used to deal with symptoms.
• If the child's allergic response is mild, check with your doctor about a trial of the offending food every six months or so.
• If the child's reactions are life-threatening, ask about having an epinephrine (Adrenalin) injector at home.
GETTING HELP
Call your doctor if:
• Your child tends to develop specific symptoms within an hour of eating certain foods
