Food Allergies Can Kill

Enjoy a peanut butter sandwich, a glass of milk, or fish fillet? These seemingly normal harmless foods can seriously upset, or even kill those who are allergic to them.

Food allergy is a reaction by the immune system to a food protein. The condition is commonly associated with asthma, hay fever and eczema.

These allergies affect 4% of children and 2% of adults in New Zealand. It runs in families. There is 50% risk of developing a food allergy if one parent has it and a 70% risk if both parents have it.

Food allergy is common in children, but many grow out of it.

Foods that cause allergies

The big eight foods that cause 90% of food allergies are cow's milk, eggs, peanuts, wheat , soy, fish, shellfish and tree nuts.

Egg and dairy allergies are the commonest in children.

Reaction to food allergy can be life threatening

When a food allergy reaction occurs, it is immediate. It can show from a few seconds to two hours after eating.

There are four types of reaction:

  • Skin – hives, eczema, swelling, itching
  • Respiratory – sneezing, asthma, shortness of breath, cough
  • Gastrointestinal – swelling, itching of lips or mouth, vomiting, reflux, colic, diarrhoea, cramps, constipation
  • Circulatory - low blood pressure, dizziness, anaphylactic shock.

Anaphylactic shock is life threatening and includes:

  • Constriction of airways
  • Shock and collapse with severe drop in blood pressure
  • Rapid pulse, dizziness.

It requires immediate action – dial 111.

An adrenaline injection and/or antihistamine drugs are given to save a life when anaphylaxis occurs.

How food allergies are diagnosed

  • By seeing what happens, if it's obvious
  • Elimination diet (starting with a low-allergy diet and gradually introducing one food at a time)
  • Skin tests
  • Other special tests.

Protecting a baby from developing food allergies

  • While pregnant or breastfeeding, don't eat peanuts
  • Delay onset of solids until six months
  • Avoid cow's milk, egg and fish until age one
  • Delay peanuts, tree nuts and shell fish until age three.

Some children can grow out of food allergies. 90% of children outgrow milk and egg allergies by age 10. 20% of children will outgrow peanut allergy. Children often out grow wheat allergy by age two.

Note that chicken and egg products are used in the manufacture of some vaccines. It's best to ask your family doctor what is in the vaccine.

How is a food allergy different to food intolerance?

The effects of food intolerance can be immediate, but can take longer to show. It can involve several foods and is not a reaction by the immune system. Also, with a food Intolerance, you can eat small amount of the food without a reaction. With a food allergy, even the tiniest amount will cause a reaction.

Common food intolerances include:

  • Lactose intolerance (cow's milk) is a deficiency of an enzyme in the body to break down lactose in milk. It causes diarrhoea, bloating and wind.
  • Irritants in food such as caffeine, spices, garlic, onions, cabbage.
  • Food chemical intolerance, e.g. to salicylates and amines. It can cause asthma, itch, hives and migraines.
  • Food toxins. Spoiled fish contains histamine which can cause similar symptoms to allergy.
  • Sulphites in wine.

Some of the symptoms of food intolerance can mimic allergy, but you never get a full collapse with intolerance.

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