Final answer:
A toddler with poor sleep and intense perianal itching is likely suffering from a pinworm infection, accurately detected through clinic observation or sample collection and treatable with specific medications.
Step-by-step explanation:
A toddler experiencing poor sleep and intense perianal itching and scratching is likely to be suffering from a pinworm infection (Enterobiasis). Pinworms, caused by Enterobius vermicularis, are small nematodes that are the most common helminthic (worm) infection in the United States, particularly affecting children. The intense itching typically occurs at night when the female worms lay their eggs in the perianal region. The transmission of this infection is through the fecal-oral route, where the scratching of the area leads to the spreading of the eggs under the fingernails, later transferring to the mouth or other surfaces, thus continuing the cycle. In clinic settings, observation of the perianal region at night, collecting eggs with transparent tape in the morning, or examining samples under the fingernails can diagnose the infection. Treatment usually involves medications such as mebendazole, albendazole, or pyrantel pamoate.