An itchy anus is the most common symptom of a pinworm infestation. It is caused by the adult worm migrating out through the anus to lay eggs. This usually occurs at night, which is when the itching will be most intense. The first signs and symptoms may not appear until one to two months or more after the person swallows the pinworm eggs.
A child with pinworms may have sleep disturbances. The child may be irritable because of the itching and poor sleep. If the infestation is severe, the person may be restless and have a poor appetite.