Allergy Testing

Skin Prick Allergy TestingHow do you test for allergies?

There are three methods of reliable allergy testing available.

Skin Prick Allergy Testing and IgE specific blood testing are used to identify allergies to a wide range of airborne allergens and foods. Patch testing is used specifically to identify the contact allergic trigger in a condition called contact dermatitis.

Skin prick testing is regarded as the gold standard allergy testing method as it carries a number of advantages over IgE specific blood testing. It is used in Allergy Ireland and all other major allergy centres.

Skin Prick Allergy Testing

What is Skin Prick Allergy Testing?

Skin Prick Allergy Testing is a safe, fast and virtually painless investigation which identifies whether a suspected allergy is present. It is performed in clinic and the results are available within 15 minutes. It is vital that the results are interpreted by an expert. Allergy Testing in Allergy Ireland is immediately followed by consultation with one of our doctors who will accurately interpret the results and tailor a management plan.

In cases where a food challenge is under consideration then occasionally both skin prick allergy testing and IgE specific bloods tests are carried out. This depends on the specific case history.

What conditions is Skin Prick Allergy Testing used for?

Skin Prick Allergy Testing is used to confirm sensitisation in IgE mediated allergic disease. This is of particular importance in food allergy and anaphylaxis, allergic rhinitis, asthma, eczema and chronic spontaneous urticaria.

What does Skin Prick Allergy Testing involve?Skin Prick Allergy Testing multistick

Skin Prick Allergy Testing involves placing a small droplet of allergen onto the skin and then introducing a tiny amount of each allergen into the skin. If allergic sensitisation is present, then a temporary bump called a wheal will form on the skin and the surrounding skin will flare red. 

Which allergens can Skin Prick Testing test for?

Skin Prick Allergy Testing can test for a very wide range of airborne allergens and foods.  

The following allergens can be tested for: 

  • Inhalant Allergens: House Dust Mite, Grass Pollen, Tree Pollens, Silver Birch Pollen, Ragweed Pollen, Feathers, Animal Dander (cat/dog/horse/rabbit) and Household Mould Spores (alternata & cladosporium).
  • Common Foods: Egg, Milk, Soya, Wheat, Potato, Tomato, Orange, Strawberry, Kiwi and Chocolate (Cocoa).
  • Nuts/Seeds (where appropriate):  Peanuts, Almonds, Cashew nut, Hazelnuts, Brazil nuts, Walnut, Pecan nut, Pine nut, Pistachio nut, Chestnut, Sesame seed, Sunflower seed.
  • Fish/Shellfish (where appropriate): Cod, Hake, Salmon, Tuna, Mackerel, Shrimp, Lobster, Crab, Clam, Mussels and Scallops.

If you would like you to be tested for something not on our list please contact us by e-mail. For example, if you bring a small sliver of fresh food then that can be tested directly. This is usually done for specific fish you suspect you may have reacted to if it is not available in allergy extract form. 

Please note: Allergy testing is carried out against wheat and not against gluten. The reactivity to gluten that is found in Coeliac disease is an autoimmune condition rather than an allergy. Coeliac disease is tested for via an antibody blood test (anti-TTG) or an endoscopic gastric biopsy.

Skin Prick Test Result Interpretation

Skin Prick Allergy Test Results

It’s easy to perform an allergy test, the skill lies in interpreting the result in the context of the patient's symptoms. Sometimes there is no link.

A positive result is measured in millimetres of wheal (skin bump) and outer flare (redness of skin). There are positive (histamine) and negative (saline) controls to ensure the accuracy of test result.

With inhalant allergens such as dust mite, pollens and animal hair the size of the wheal and flare is important but does not always reflect the symptoms. For example a patient will occasionally show a very large wheal and flare (say to dust mites) but not show many symptoms. Equally a relatively small reaction (say to cat hair) in someone only recently exposed to cats is usually very important as within a year of continuous exposure the allergic reaction will probably have increased significantly (as will the patient’s symptoms).

What are the requirements for Skin Prick Allergy Testing?

  • Anti-histamines must not be taken starting 5 days prior to the testing date. This includes oral antihistamines and topical antihistamine nasal sprays (Ryaltris, Dymista) and antihistamine eye drops (Opatanol). 
  • Skin Prick Testing should not be carried out within 4 weeks of a systemic allergic reaction or anaphylaxis. This is due to the risk of false negative test results.
  • Skin Prick Testing should be avoided during pregnancy due to the remote risk of a systemic reaction trigger early labour.
  • Steroid creams should not be applied to the area of skin being used for testing within 24 hours prior to the test..

Patch Testing

What is Patch Testing used for?

Patch Testing tests for allergic triggers in a condition called Contact Dermatitis. It does not test for food or inhalant allergies. 

What does Patch Testing test for?

Patch Testing tests for common chemicals in our daily environment and workplaces that cause skin reactions when they come in contact with some peoples skin. They include cosmetics, hair dye, fragrances, sun cream, lanolin, dental metals and adhesives. These reactions only occur in sensitised individuals. 

Further Information on Patch Testing