The difference is access to testing. Most of the people in the US who "test" positive for an allergen aren't actually allergic to it, but that is often not explained properly.
Simply, allergists have three types of testing: skin test, blood test, actual exposure. If you can eat something without a reaction, it doesn't matter what the skin and blood tests showed (they can be "positive" for other reasons). Skin and blood tests are mostly used to determine severity of an allergy after exposure has already proven to be a problem.
But allergy testing is covered by insurance (and it's VERY profitable), so a ton of allergists will do skin and blood tests on people who don't need it, and now there are independent scam companies doing "allergy" testing by mail for curious people.
Simply, allergists have three types of testing: skin test, blood test, actual exposure. If you can eat something without a reaction, it doesn't matter what the skin and blood tests showed (they can be "positive" for other reasons). Skin and blood tests are mostly used to determine severity of an allergy after exposure has already proven to be a problem.
But allergy testing is covered by insurance (and it's VERY profitable), so a ton of allergists will do skin and blood tests on people who don't need it, and now there are independent scam companies doing "allergy" testing by mail for curious people.