Final answer:
The most likely diagnosis for the young girl with symptoms of perianal itching and the discovery of bean-shaped white eggs is Enterobiasis, a common pinworm infection treatable with antiparasitic medications.
Step-by-step explanation:
The most likely diagnosis for the 8-year-old girl with two weeks of perianal pruritus and the presence of bean-shaped white eggs revealed by the "scotch tape test" is Enterobiasis, also known as a pinworm infection. The symptoms and the finding of eggs during the examination are characteristic of enterobiasis, caused by the worm Enterobius vermicularis. This condition is common among children and can be easily transmitted within households, particularly among siblings. The standard treatment options include antiparasitic medications such as mebendazole, albendazole, and pyrantel pamoate.