Final answer:
A positive skin test associated with pre-pen is indicated by a wheal and flare response, which is a soft, pale swelling at the test site surrounded by redness.
Step-by-step explanation:
A positive skin test associated with pre-pen is indicated by a wheal and flare response, which is a soft, pale swelling at the test site surrounded by redness. When pre-pen is injected into the epidermis, it can trigger a type I allergic reaction in individuals who are allergic to penicillins. This allergic reaction occurs due to the release of histamine and other granule mediators, leading to fluid leakage from blood vessels and increased blood flow to the area.