In refering to perianal itching, which parasite is commonly responsible?

Pinworm is commonly responsible for perianal itching, particularly in children. The pinworm, or Enterobius vermicularis, is a small, white, thread-like worm that primarily infects humans. Infection occurs when the eggs, which are microscopic and easily spread, are ingested or inhaled. Once inside the intestine, these eggs hatch, and adult worms develop.

Female pinworms migrate to the perianal area to lay their eggs, often during the night, which leads to intense itching in that region. This itching can result in irritability, discomfort, and even sleep disturbances for affected children.

In contrast, other parasites mentioned do not primarily cause perianal itching. Roundworms, hookworms, and tapeworms have different life cycles and modes of transmission, and their clinical presentations typically do not include pruritus in the perianal area as a significant symptom.