One extreme example is a psychological condition called delusory parasitosis where people believe their bodies are infested with mites or fleas scurrying over and under their skin, making them itch incessantly.

一个极端的例子是一种叫做妄想性寄生虫病的心理状况，人们认为他们的身体被螨虫或跳蚤滋生，在他们的皮肤上下窜动，使他们不停地发痒。