Skin prick allergy testing

What is skin prick allergy testing?

A skin prick allergy test (also referred to as a 'Skin Prick Test' or 'SPT') is a way of finding out if you have any allergies to specific things. There are two types of allergy skin tests, but the skin prick test is the most commonly used and is recommended as the main method of identifying most allergic reactions.

How does the skin prick test work?

The doctor puts a drop of a potential allergen on your skin (normally on the arm or on the upper back) and then pricks the skin through the drop. If the skin develops a reaction - this is generally where the skin near the prick reddens and becomes bumpy, or a weal appears - then this is a positive indication that you're allergic to that allergen.

Often several different potential allergens are tested at the same time and reactions appear within 15-20 minutes if at all. Any redness and bumps on the skin disappear after around an hour. The prick test is not painful, although young children may become upset.

Why might I need a skin prick allergy test?

Your doctor may recommend the test to rule in or out specific allergies that may be causing a specific symptom. The following allergens can be responsible for asthma type symptoms eg wheezing, coughing and shortness of breath...

  • Insect related allergies
  • Food related allergies (common allergens include dairy products, eggs, wheat, soy, nuts (various), fish and shellfish)
  • Medicine related allergies (the most common is penicillin)
  • Latex related allergy (eg latex gloves, condoms, balloons)

How should I prepare for a skin prick test?

You may need to stop taking some medications (especially allergy medications) a week before the test.

Are there any risks with skin prick testing?

Skin prick testing is relatively low risk, although very rarely larger allergic reactions do occur. Prior to the test your practitioner will ask if you have any known allergies