Pinworms
These tiny organisms crawl along the anal margin and produce lots of itching, especially at night. Most common in school-age children, they’re transmitted by direct contact, usually via the fingernails. The itching can drive your child crazy, and in girls it can cause irritation all the way to the vagina.
The diagnosis is made by looking at the anal margin, which will be quite irritated. You may even catch a glimpse of these tiny white wriggling creatures, which also sometimes turn up in the stool.
Your doctor will treat pinworms with two pills taken a week apart. Before that pill takes action, the itching can be alleviated with an antihistamine like Benadryl. Don’t go crazy disinfecting every piece of clothing and linen in the house; pinworms don’t live long outside the body.
If the itching reappears after treatment, the whole family may have to be treated to prevent the recurrence of pinworms; even if adults rarely show symptoms, they can be carriers.