Skin Allergy Testing
Skin allergy testing is a convenient and prompt method of allergy testing with results available within 15 minutes.
It is performed to help in the diagnosis of acute allergies, including food allergies and environmental allergic diseases such as
asthma and hay fever.
Skin prick testing is a useful way of following changes in the level of allergy antibody (IgE ). Reduction of this level can indicate
tolerance to the allergic ( agent causing the allergy) and growing out of the allergy.
Allergy test results cannot be used on their own and must be considered together with your medical history.
The size of the skin prick test result is a guide to the amount of allergy antibody in the skin and indicates the likelihood of reacting
but cannot indicate the type or severity of the reaction. There are no tests which will indicate whether someone will have
anaphylaxis or not.
Skin testing is more accurate in predicting a negative reaction to an allergen. If negative it can indicate up to a 95% confidence
that there will not be a reaction (But not 100% !).
If positive there may be some who are not allergic at all! This is known as sensitisation only and is more likely if the skin test
result is small.
The only true method to see if there is a definite allergy or an allergy has resolved is to challenge the person with the allergen.
This is only done with medical supervision and only when appropriate.
Skin Allergy testing is not a reliable way of confirming suspected reactions to aspirin, chlorine, perfumes sunscreen or food
additives, and you will need to discuss such concerns with your doctor.
How is it Performed?
Skin testing is performed on the back. After marking the back
with a pen the allergens to be tested are placed on the back and
a prick through them is made with a sterile lancet. Sometimes
fresh foods may be used with the lancet “pricking” the food then
the back. This puts a small amount of the allergen into the outer
layers of the skin. There is no blood involved.
It is best to have the child sitting on a parents lap facing them
with legs straddled each side of the parent’s waist. The parent
holds the child’s upper arms and brings close in to their chest
The tests are usually well tolerated, can be a bit uncomfortable
with itch developing but will subside in an hour or so. A cold
compress can give great relief.
This video demonstrates testing on an infants bach using a fine
needle. We use a "Lancet" a small piece of metal with a 1mm
point.
Bad Reactions
Reactions to skin prick testing are rare but are described. There are always medications to treat any reaction should this
occur.
Severe allergic reactions from allergy testing in asthma or hay fever are very rare.
Preparation for Testing
No Antihistamines
The test reaction causes the skin allergy cells (Mast Cells) to release histamine
which produces the itch, redness and wheal (hive) that is measured. This
reaction will not be observed if antihistamines have been given.
No antihistamines for 7 days prior to testing.
Common antihistamines are:
Claratyne, Aerius, Dimetapp, Demazin, Phenergan, Polaramine, Telfast, Zyrtec.
Some cold and ‘flu mixtures contain antihistamine.
If you are unsure please call for advice.
Skin Creams
Avoid any creams on the upper back if possible as it can be difficult to do the test as the allergy agents can run into each other.
Good Health
Please notify if your child has a cold / ‘flu or asthma as this may need to reschedule the testing.
Medicare rebates are available for Skin Allergy tests or specific IgE tests in Australia.
Further Information:
ASCIA Allergy Testing
(Australasian Society of Clinical Immunology and Allergy)
Copyright © Dr David A Cutting 2015
Dr Rodney Ford, Christchurch New Zealand
Skin Allergy Testing
Skin allergy testing is a convenient and prompt method of allergy testing with results available within 15 minutes.
It is performed to help in the diagnosis of acute allergies, including food allergies and environmental allergic diseases such as
asthma and hay fever.
Skin prick testing is a useful way of following changes in the level of allergy antibody (IgE ). Reduction of this level can indicate
tolerance to the allergic ( agent causing the allergy) and growing out of the allergy.
Allergy test results cannot be used on their own and must be considered together with your medical history.
The size of the skin prick test result is a guide to the amount of allergy antibody in the skin and indicates the likelihood of reacting
but cannot indicate the type or severity of the reaction. There are no tests which will indicate whether someone will have
anaphylaxis or not.
Skin testing is more accurate in predicting a negative reaction to an allergen. If negative it can indicate up to a 95% confidence
that there will not be a reaction (But not 100% !).
If positive there may be some who are not allergic at all! This is known as sensitisation only and is more likely if the skin test
result is small.
The only true method to see if there is a definite allergy or an allergy has resolved is to challenge the person with the allergen.
This is only done with medical supervision and only when appropriate.
Skin Allergy testing is not a reliable way of confirming suspected reactions to aspirin, chlorine, perfumes sunscreen or food
additives, and you will need to discuss such concerns with your doctor.
How is it Performed?
Skin testing is performed on the back. After marking the back
with a pen the allergens to be tested are placed on the back and
a prick through them is made with a sterile lancet. Sometimes
fresh foods may be used with the lancet “pricking” the food then
the back. This puts a small amount of the allergen into the outer
layers of the skin. There is no blood involved.
It is best to have the child sitting on a parents lap facing them
with legs straddled each side of the parent’s waist. The parent
holds the child’s upper arms and brings close in to their chest
The tests are usually well tolerated, can be a bit uncomfortable
with itch developing but will subside in an hour or so. A cold
compress can give great relief.
This video demonstrates testing on an infants bach using a fine
needle. We use a "Lancet" a small piece of metal with a 1mm
point.
Bad Reactions
Reactions to skin prick testing are rare but are described. There are always medications to treat any reaction should this
occur.
Severe allergic reactions from allergy testing in asthma or hay fever are very rare.
Preparation for Testing
No Antihistamines
The test reaction causes the skin allergy cells (Mast Cells) to release histamine
which produces the itch, redness and wheal (hive) that is measured. This
reaction will not be observed if antihistamines have been given.
No antihistamines for 7 days prior to testing.
Common antihistamines are:
Claratyne, Aerius, Dimetapp, Demazin, Phenergan, Polaramine, Telfast, Zyrtec.
Some cold and ‘flu mixtures contain antihistamine.
If you are unsure please call for advice.
Skin Creams
Avoid any creams on the upper back if possible as it can be difficult to do the test as the allergy agents can run into each other.
Good Health
Please notify if your child has a cold / ‘flu or asthma as this may need to reschedule the testing.
Medicare rebates are available for Skin Allergy tests or specific IgE tests in Australia.
Further Information:
ASCIA Allergy Testing
(Australasian Society of Clinical Immunology and Allergy)
Copyright © Dr David A Cutting 2015
Dr Rodney Ford, Christchurch New Zealand
