Hi, welcome to the forum, you may be
allergic to blue berries.
Allergic reactions can manifest as various forms which includes itching, rash, hives, breathing difficulty, stomach pain, selective areas can be involved. May be due to poor skin integrity in the wrist area or presence of any other allergen which is in contact with wrist.
As allergic reactions are IgE mediated, blood tests will show increase in these levels secondary to a food allergy.