Frequently Asked Questions: General Allergy

Are allergies increasing?

Recent Australian research shows that 1 in 10 babies will develop a food allergy by one year of age. The reasons for the ongoing increase in allergic conditions such as food allergy, eczema and hay fever are complex and we still don’t fully understand them.

Although babies with a family history of allergy have a higher chance of developing an allergy, babies with no family history can still develop allergies.

Why is food allergy increasing?

We currently do not know why food allergy has increased so rapidly in recent years, particularly in young children. It appears to be a mix of a western lifestyle and environmental factors – with no single trigger factor.

Possible reasons include:

  • Delaying the introduction of common allergy causing foods such as egg, peanut or tree nuts.
  • The hygiene hypothesis which suggests that less contact with microbes in early childhood may increase the chance of developing allergy. A more recent version of the hygiene hypothesis suggests that the type of the micro-organisms to which the mother and baby are exposed to may be important.
  • Methods of food processing food such as roasted versus boiled peanuts or baked egg versus lightly cooked egg, may affect whether the food is more or less likely to cause food allergy.
  • Development of food allergy by the skin coming into contact with the food before the food has been eaten by the baby, for example through the use of moisturisers containing foods such as nut oils or cow’s or goat’s milk.
  • Use of medicines to decrease gastric acid production.
  • Vitamin D status in the first year of life.

These areas require additional research studies, several of which are underway.

Does food allergy run in the family?

Many children with food allergy will have a parent or a sibling who suffers from some type of allergic condition such as eczema (atopic dermatitis), asthma, hay fever (allergic rhinitis) or food allergy.

Most of the time, children with food allergy do not have parents with food allergy. However, if a family has one child with a food allergy, their brothers and sisters have a slightly higher chance of having a food allergy themselves, although that risk is still quite low.

Are all food allergies severe?

Most babies with food allergy only experience mild symptoms. Mild symptoms include hives, stomach/tummy pain or vomiting. Symptoms such as difficulty breathing or talking (vocalising) due to throat or tongue swelling or breathing difficulty, or dizziness due to a drop in blood pressure or tongue swelling, are less common, however these indicate a potentially life threatening severe allergic reaction (anaphylaxis).

What are the signs and symptoms of an allergic reaction?

Allergic reactions usually occur quickly – within minutes (although they can take up to 2 hours). Other reactions to foods may be delayed.

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If I have a positive allergy test, does this mean I am allergic to the foods?

A positive skin prick test (SPT) or allergy blood test means that the body’s immune system has produced a response to a food, it does not mean that the person is necessarily allergic to that food.

About 1 in 3 people with positive blood allergy tests or skin tests to foods will not be allergic to that food, especially if they have not previously experienced an allergic reaction to that same food when eating it. For this reason, it is not generally recommended to screen people for allergies to foods using these tests.

How accurate are alternative allergy testing methods?

Unproven claims to cure or detect allergy are only strictly regulated by government, medical boards, and advertising regulators, if the practitioner is a registered medical practitioner.

Currently, there are no strict regulations for unproven diagnostic techniques or devices. These devices and tests can be TGA approved in Australia without having to prove that they work.

There are many methods that claim to test for allergy. These include cytotoxic food testing, kinesiology, Vega testing, electrodermal testing, pulse testing, reflexology and hair analysis. These tests have not been proven to work and may lead to unnecessary, costly and (in the case of some changes in diet) dangerous avoidance strategies.

No Medicare rebate is available in Australia for these tests and the use of these methods is not recommended.

Should I avoid pets?

There is no reason to remove pets from your home unless a person is already allergic to them. Some research studies have shown that having dogs may help lower the chance of children developing allergies.

Will dust mite avoidance measures reduce the risk of allergy and asthma developing?

No, measures to reduce house dust mite are difficult and don’t help to prevent allergies or the onset of allergic rhinitis (hay fever) or asthma. However, if you have confirmed house dust mite allergy then minimisation measures may help reduce symptoms.

Will allergen immunotherapy (desensitisation) prevent allergy?

Allergen immunotherapy or desensitisation is a treatment for someone who already has an allergy. Allergen immunotherapy does not help to prevent food allergy.

Research suggests that if a child has hay fever (allergic rhinitis), having allergen immunotherapy for their trigger may reduce the chance of the child developing asthma.

Talk to your doctor if you would like to know more about allergen immunotherapy.