To help find out if you have any allergies
Sue Ferguson (Allergy Technician) does skin prick testing for food allergens and also for inhalants and environmental allergens. She tests both children and adults (children from 4 months onwards). She interprets but does not manage the results, which you can take to your health professional for advice.
These skin prick tests can only identify allergy. They do not detect food intolerances (such as gluten and dairy intolerance).
Skin prick testing (SPT) detects if you have a food or environmental allergy. The common food allergens that she tests for are: milk, egg, peanut, soy, wheat, fish, and cashew.
Also, the environmental allergens: house dustmite, ryegrass pollen, birch tree pollen, cat fur, dog hair, tree pollen.
Other allergens can be tested for by request (if the allergen testing solution is available).
Most people are unaware of their allergies. Allergies affect about 25% of the population. But, did you know that there are no special “allergy symptoms”.
Negative Food Skin Tests: When there is no bump/wheal (0-2mm) after 20 minutes: this means you have not got a current allergy to any of these foods. But, a negative skin test does not rule out any food intolerances. Gluten and dairy intolerances cannot be detected by SPT. This means that a trial of either a dairy-free or gluten-free diet is necessary for you to work out if this food is causing any symptoms.
SPTs will usually be negative if you have slow-onset (or delayed-onset) symptoms: that is an adverse food reaction occurring after several hours of eating. With gut/bowel symptoms alone, then SPT are usually negative. With chronic urticaria, usually a precipitating factor cannot be detected by SPT.
Positive Food Skin Tests: When there is a bump/wheal (3mm or more) within 20 minutes: this means you have a current, or past allergy to the food. It diagnoses an allergy, but not an intolerance. The bigger the bump size, the stronger the allergic reaction. In children, this is indicative of current food allergy, and food elimination may be needed. However, a small bump might only indicate a “sensitivity” rather than a clinical allergy (meaning that this food is not causing any symptoms). In adults, a positive SPT can mean either a current allergy, or evidence of past allergy.
INHALANT / ENVIRONMENTAL ALLERGENS
A positive SPT indicates that you have a current allergy to that allergen. The most common symptoms are hayfever: runny nose, sneezing, itchy eyes. House Dust Mite allergy may respond to mite reduction. Birch pollen allergy is often associated with the “Oral Food Allergy Syndrome”.