How Is It Diagnosed?

To identify an allergy to ragweed or one of its relatives, requires a careful medical history, a physical exam and testing. The main approach to confirm a suspected allergy is the skin sensitivity test.

For this, the skin is scratched or pricked with extract of ragweed pollen. In sensitive people, the site will turn red, swollen and itchy. Sometimes blood tests are used to see if an antibody to ragweed is present. This is sometimes necessary, but it takes longer for processing by a laboratory and it is more expensive.