Talk of food allergy is everywhere. Understandably so--food allergy is a reality in our 21st century lives. Because of the serious side effects that can occur when a child with an allergy to peanuts accidentally eats peanuts or products that contain peanuts, our children are no longer able to take peanut butter sandwiches or other foods with nuts to school. When someone has a food allergy, their immune (or defense) system responds to proteins in food that the body mistakenly believes is harmful. In food-allergic people, the body makes antibodies to the offending food and when a person ingests that food the body releases many chemicals including histamine in order to protect the body. This release of chemicals can cause a multitude of symptoms that can affect the respiratory system, the gastrointestinal (GI) tract, the skin and the cardiovascular system. Symptoms occur within minutes up to 2 hours after ingesting the offending food and can include:
- Tingling of the mouth and lips
- Itching skin
- Skin rash
- Hives
- Abdominal cramps
- Diarrhea or vomiting
- Swelling of the tongue or throat
- Difficulty breathing
- Drop in blood pressure
- Death (extremely rare)
Anaphylaxis is a severe allergic reaction that occurs very quickly and may cause death if not treated immediately. Children who suffer from food allergy and may be at risk for anaphylaxis should carry an Epi-pen ®, which is an injectable medication that can be administered at home, school or in the daycare setting. An Epi-pen ® contains epinephrine (or adrenaline), a powerful medication that can help reverse the effects of an anaphylactic reaction. Once administered, it is important that you continue to take your child to the nearest emergency room for evaluation.
It has been estimated that over 90 % of food allergies are caused by 8 different foods. The most common food allergens include:
- Milk
- Soy
- Eggs
- Peanuts
- Tree nuts
- Wheat
- Fish
- Shellfish
Many children grow out of their allergies to milk, soy and eggs. However, allergies to nuts, fish and shellfish tend to be life-long allergies. The only treatment currently available for food allergy is the avoidance of the offending allergen. This means careful reading of all labels of packaged foods and education about the different words on a food label that can indicate the presence of a food allergen. Health Canada is currently reviewing the way in which foods are labelled and in the very near future it will be mandatory for food labels to state which food allergens they contain. In the meantime, however, careful evaluation of all food labels is the only defense against accidentally ingesting foods that your child is allergic to.
Milk Allergy vs. Lactose Intolerance
Milk allergy should not be confused with lactose intolerance. People with lactose intolerance lack the enzyme (which is found in the small intestine) required to digest the sugar in milk called lactose. Lactose intolerance can cause bloating, stomach pains and diarrhea. However, milk protein allergy is an immune system response to the proteins in milk. The treatment of lactose intolerance may differ from the avoidance of all milk products. It is even possible to introduce lactose slowly over time to become used to this milk sugar again. If you suspect you have lactose intolerance speak with your doctor about ways to reduce the lactose in your diet.
Wheat Allergy is not Celiac Disease
Celiac disease is not the same thing as having a wheat allergy. While wheat allergy is an immune system response to the protein in wheat, celiac disease is intolerance to gluten. Gluten is found in grain products including wheat, rye and barley. Celiac disease is diagnosed by a biopsy of the small intestine and requires extensive teaching to ensure gluten is avoided in the diet.
How is Food Allergy Diagnosed?
Food allergy can be diagnosed by skin-prick testing or by a blood test. The results of either “prick testing” or the blood test must be done in conjunction with a history of your child’s symptoms for the doctor to make the final diagnosis. In skin-prick testing a small amount of allergen is injected in the arm or on the back in a controlled environment. Reactions are then monitored and evaluated by the allergist to confirm the diagnosis of food allergy. Alternately, a blood test called RAST or Immuno-cap can be done in certain situations.
Can allergy be prevented?
Exclusive breastfeeding for at least 4 months can reduce the risk of atopic diseases, which include asthma, allergy, and eczema. This may be especially beneficial in high-risk infants, who have at least one parent or sibling with atopy. This is currently the best and only defense we have against the development of food allergy.
For more information on food allergy in Canada visit the Allergy, Asthma Information Association at www.aaia.ca or Anaphylaxis Canada at www.anaphylaxis.ca. Health Canada also provides excellent resources of how to avoid specific food allergens. Health Canada’s website can be accessed at www.hc-sc.gc.ca.
Written by Daina Kalnins and Joanne Saab
Our Experts: Daina Kalnins is a registered dietitian and Academic and Clinical Specialist working at the Hospital for Sick Children in Toronto. Joanne Saab is a registered dietitian in paediatrics at McMaster Children’s Hospital in Hamilton. Daina and Joanne have co-authored the best selling Better Baby Food (SickKids, 2nd ed- September 2008) Better Food for Kids, and Better Food for Pregnancy. Daina is also the author of Better Breastfeeding and YUM.
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