They are difficult to detect in dry hair even when the head is closely inspected. 머릿니는 가려움증을 유발하는 경우가 많지만, 특히 최근에 머릿니가 머리에 생겼을 때 항상 그런 것은 아닙니다. Head lice cannot fly, jump or swim, but spread by clambering from head to head.