Where to prick the apple for skin testing?

Mal d 1 is not equally distributed over the apple. We aimed to examine the influence of the location of pricking in the apple on prick-to-prick skin prick test (PTP) results. PTPs were performed in autumn 2007 and spring 2008, before the birch pollen season, in 32 Dutch adults with symptoms of oral allergy to fresh apple, using apples harvested in autumn 2007. PTPs with fresh intact and unpeeled Pink Lady, Golden Delicious, Elise, Santana and Modi apples were performed using material obtained from approximately 2cm near the stalk (top), and the middle region. All PTP responses were greater when performed with apple material near the stalk than from the middle region. In 2007, these differences were statistically significant for Pink Lady, Golden Delicious and Elise, and in 2008, for Pink Lady and Modi. When performing PTPs, the apple should be pricked near the stalk rather than in the middle.