New research into skin-prick allergy testing

Tuesday, 29 May 2007 01:24

A standard skin-prick test, which involves placing a drop of allergen extract on the skin, then pricking the skin through the drop, is frequently used as a screen for allergies.  An indicative positive result is diagnosed if a hive reaction develops around the site of the skin prick where the hive measures 8 millimetres or more.

It has long been recommended that skin-prick testing is used as an indicative diagnostic tool that should not be used in isolation when diagnosing food allergies; additional diagnostic tools should be used in addition to an assessment of medical and family history.

However, new research published by Wainstein and colleagues studied 84 children at Sydney Children’s Hospital in Australia who tested positive to having a peanut allergy using the standard skin-prick test.  The skin-prick test became 100% accurate when the hive measured 15 mm or more.

In this study, 67% of the children in the study with hives measuring between 8 and 10 mm after skin-prick testing proved to be allergic when given peanut to eat under hospital supervision.

“For many with a positive result on the skin-prick test, it would be worth doing a peanut challenge in a hospital environment,” Wainstein says.

Journal reference: Pediatric Allergy and Immunology (vol 18, p 231)