Think you have an allergy? Here’s how to tell if you really do

Sneezing, skin rashes and wheezing can all signal an allergy. Here are the tests you need to have that may help you pinpoint the source.

Australia is thought to be the allergy capital of the world, with more than five million of us living with allergies.

And the epidemic is rising.

Allergy occurs when a person’s immune system reacts to substances most people find harmless.

These substances (allergens) are found in things such as dust mites, pollen, pets, ticks, insects, mould, foods and some medications, the Australasian Society of Clinical Immunology and Allergy (ASCIA) explains.

An allergic reaction can be mild to severe, such as anaphylaxis, which is a medical emergency, explains nutritional lifestyle medical doctor Dr Amy Carmichael.

“Some people think allergies are all the same – they’re not,” Dr Carmichael says.

“They vary in severity, from acute to chronic.”

Allergy symptoms may include sneezing, a runny nose, breathing problems, headaches, skin rashes, wheezing, persistent cough and swelling of the lips, face and eyes.

How allergy tests can help

Allergy tests may help pinpoint what is causing your sensitivity or reaction.

Tests should always be done by a trained healthcare professional, to determine if it is indeed an allergy that is causing your symptoms.

Blood tests and skin prick tests are the most common types of tests, according to ASCIA.

Skin prick tests, usually on the forearm or back, introduce an allergen into the skin’s top layer.

A small itchy lump or reddening appears within 20 minutes if the result is positive.

Most allergists in Australia primarily use skin prick tests, which currently offer the best accuracy, says the Murdoch Children’s Research Institute’s Dr Tim Brettig (whose research recently uncovered the prevalence of cashew allergy in Australian infants for the first time).

“It gives us a probability of how likely you are to be allergic,” Dr Brettig says.

“But a positive test doesn’t always mean the person is allergic.”

Blood tests can be done when skin prick tests are not easily available when you have severe eczema or you are taking medicine that can affect the results, according to ASCIA.

They may also be useful if your skin prick test is inconclusive.

Results may take up to a week.

Dr Brettig says most blood tests try to measure the number of antibodies directed towards the suspected allergen, offering a probability of how likely you are to be allergic.

How reliable are allergy tests?

Dr Brettig says skin prick and blood tests are currently the best forms of allergy testing, but they aren’t accurate enough to be used to screen for any allergies before exposure.

“Our blood tests in general can have a lower accuracy, but there’s newer tests that may be used in our clinical practice over the next few years that can help to increase the accuracy,” he says.

The reliability of allergen extracts used by allergists may also vary, potentially making test results inaccurate, Dr Brettig adds.

“We usually get around that by asking families to bring in a small portion of the fresh allergen food.”

Other allergy tests are available but the testir results are not scientifically validated, so they could over-diagnose or even miss allergies, Dr Brettig says.

On its website, ASCIA lists testing methods it doesn’t recommend, including cytotoxic food testing, kinesiology, hair analysis, Vega testing, electrodermal testing, pulse testing, reflexology, and immunoglobulin G (IgG) to foods.

If you’re interested in taking part in allergy research, visit the National Allergy Centre of Excellence Allergy Studies Directory.

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Written by Melissa Iaria.