Which allergy testing method involves injecting a small amount of antigen under the skin?

Which allergy testing method involves injecting a small amount of antigen under the skin?

• A. Scratch test
• B. Intradermal allergy testing
• C. Skin patch test
• D. Prick test

Answer: (B)

Introducing antigen under the skin by injection is intradermal allergy testing. It places a small amount of allergen into the dermis, producing a localized wheal-and-flare reaction if the person is sensitive. This test is more sensitive than surface skin tests and is used when initial results are inconclusive or for certain allergens like venom or penicillin, but it carries a higher risk of reaction and must be performed by trained staff. In contrast, scratch or prick tests expose the allergen to the epidermis with a light scratch or prick, not injection into the dermis, and the skin patch test applies allergens on a patch to the back for a delayed reaction assessed after 48 hours.

Introducing antigen under the skin by injection is intradermal allergy testing. It places a small amount of allergen into the dermis, producing a localized wheal-and-flare reaction if the person is sensitive. This test is more sensitive than surface skin tests and is used when initial results are inconclusive or for certain allergens like venom or penicillin, but it carries a higher risk of reaction and must be performed by trained staff. In contrast, scratch or prick tests expose the allergen to the epidermis with a light scratch or prick, not injection into the dermis, and the skin patch test applies allergens on a patch to the back for a delayed reaction assessed after 48 hours.