What could be more "yuk" than pinworms? Yet these harmless little beasties are fairly common among children, even those who do not have the usual symptom of itching. It is estimated that 40 million people in the U.S. have pinworms at any given time. Approximately 10 percent of children in childcare are likely to be infected with pinworm (often called "seat worms" or "thread worms"). Adults are less commonly infected, although they can have them, too.
First, what is a pinworm? The technical name is "enterobius vermicularis"--some very big words for animals that are generally less than half an inch in length. The worms look like tiny gray bits of thread--that wiggle! The trouble they cause also is way out of proportion to their size.
The tiny pinworm, a variety of roundworm, is whitish in color. Pinworms are difficult to find because most of the time they live happily in the lower part of the large intestine, just inside the anus. At night, while the child is sleeping and not physically active, the pregnant female worms come out to lay eggs in the folds of skin around the anus. They then go back inside the body and shortly die. Within two-four weeks, the eggs hatch and the adult females repeat the process of coming out of the anus, laying eggs, and going back in.
Transmission of Pinworms
There are different types of pinworms, but only one affects humans. Dogs and cats also have pinworms, but they are different from the pinworms that infect people. Dog and cat pinworms cannot live in human beings, and pinworms cannot live in them so frequently heard warnings about "catching" pinworms from the pet are not correct.
Transmission of pinworms occurs by swallowing the eggs. This can happen when a child scratches "back there" and picks up the eggs under his or her fingernails. Then, the child can pass the nearly invisible eggs on by touching another child, or an object such as a toy, from which the eggs can be picked up by a playmate. This second child, who then has pinworm eggs on his hands, sticks his fingers in his mouth; the eggs go into the intestine, where they mature, and the cycle starts all over again. Eggs are so tiny that they can even float in the air when bedclothes or underwear are shaken. Eggs are transmitted from shared toys, clothing, bedclothes, toilet seats, door handles, and baths. The infected child can reinfect himself by putting his fingers in his mouth--ugh!
Caregivers also can become part of the transmission cycle as you pick up toys and play with an infected child. Caregivers also may come in contact with the pinworm eggs during diapering or assisting with toileting.
Symptoms and Diagnosis
At their worst, pinworms can cause itching. However, most people with pinworms, whether children or adults, have no symptoms at all. They are happily unaware of their infections, but they may sleep restlessly. Sometimes bed wetting can result. Uncommonly, pinworms can irritate a little girl's vagina. Contrary to many myths, pinworms do not cause convulsions, abdominal pain, loss of appetite, or grinding of the teeth. They are not a sign of poor hygiene or neglect. They are not a reason to panic.
Because the females come out to lay their eggs at night, a time-honored means of diagnosis is to examine the skin around the anus with a flashlight a couple of hours after the child has gone to bed. Look for the tiny threadlike worms on the skin around the anus as they lay their eggs. A better method that can be done any time of day, is to wrap a piece of cellophane tape--sticky side out--over the end of a flat stick, such as a tongue blade or craft stick and gently touch the sticky stick to the skin around the anus. When the tape is removed and put on a microscope slide, sticky side down, any pinworm eggs will be visible through the microscope. This can be done in a doctor's office, or the parent may do it at home and then take the taped stick to the doctor's office.
Treatment and Prevention of Reinfection
In years past, a brilliant purple medicine, gentian violet, was the only remedy for pinworms. Unfortunately, it also stained clothing purple. Seeing purple-stained training pants hanging on a clothesline to dry was an indication of pinworms in the neighbor's kids. Fortunately, treatment has changed. Treatment involves giving a dose of prescription medication, usually in the form of a chewable tablet. The medicine kills the worms, but not the eggs, so a second dose of the medication is given two or three weeks later to kill worms that hatched from the eggs that were present at the time of the earlier treatment. The success rate with this treatment is about 95 percent. There is no effective over-the-counter treatment or home remedy for pinworms.
Even if only one child in a family has pinworms, it is very important that everyone in the household be treated with the pinworm medicine at the same time, even if they do not have any signs of pinworms. All the sheets, blankets, towels and clothing in the house should be washed in hot water, and everyone's fingernails (which might hold the worm eggs) should be carefully cleaned and cut short.
A child with pinworms should be excluded from the childcare environment until after the first dose of medication has been given. Although the adult worms are killed, the child will still have pinworm eggs so proper precautions, should be followed. Caregivers also should check with the parents or guardian two weeks after the first dose to assure that the second dose of medication has been taken.
As with so many other potential health problems, the best way to prevent transmission of pinworms is by frequent, thorough hand washing by both caregivers and children. Keeping fingernails trimmed short also is helpful, and nail biting should be discouraged.
Pinworm eggs can live away from the human body for a couple of weeks. Eggs often are found on bed linens, clothes, toilet seats, toys, carpet, etc. The usual good housekeeping measures--cleaning floors, vacuuming carpets, and washing toys each day--are generally sufficient to remove these eggs from the childcare environment. Bed and cot linens should be laundered at least weekly. If a child is diagnosed with pinworms, his or her sheets, blankets, and any personal stuffed toys should be washed before he or she returns to the childcare setting.
Donald Palmer, MD
Chairman of the Child Care Committee, Alabama Chapter, American Academy of Pediatrics