Pinworms (Threadworms; Enterobius Vermicularis)
Pinworms, a member of the roundworm family, are one of the most common intestinal parasites in the world, infecting over 40 million individuals in the United States alone each year. While this parasitic infection may be bothersome, the main symptom being rectal itching, they are considered one of the least dangerous parasitic worms. While pinworms occur most often among school-aged children, people of any age and socioeconomic class can contract a pinworm infection.
Pinworms live in the human intestines, with an adult male pinworm generally measuring 1 mm (.0393 inches) to 4 mm .157 inches) long, and an adult female measuring about 8 mm (.315 inches) to 13 mm (.512 inches) long. The pinworm itself has a long, pin-shaped rear end, which gives the parasite its name. Pinworms are contracted through close contact with someone who has them, and ingesting the microscopic eggs that the pinworm female lays.
It can take up to one to two months after ingesting pinworm eggs for pinworm symptoms to appear. It is at this point that the female pinworm migrates from the large intestine to the area around a person's rectum to lay more eggs. When the rectal area is scratched, pinworm eggs may be transferred onto the fingers and into a person's surroundings, where they can survive for up to three weeks. Pinworm symptoms are generally worse at night, when the female pinworms are most active.
Pinworms are generally diagnosed by a doctor from a stool sample. Adult pinworms may be visible to the naked eye, appearing like pale threads in an individual's stool. They also can occasionally be observed in or around the anus. Pinworms do not generally migrate to other areas of the body, nor do they cause any symptoms more severe than itching, however it can escalate to the point where the itching is so bothersome that a patient cannot get a good night's sleep. Pinworms are not zoonotic, meaning they cannot be transferred from animals to humans.
Pinworms can be treated with prescription or over-the-counter worming medications. While it is not necessary to treat all members of a household if one has a pinworm infection, it might be recommended in certain situations by a medical professional. Pinworm medications kill adult pinworms, and are thus administered usually in two doses, two weeks apart. Sanitizing household objects such as bedding and toilet seats is recommended, and observing good hygiene practices generally prevents reinfection. A doctor or other qualified medical professional can perform the required tests, prescribe the needed medication and give the proper guidance as to how to treat pinworms.
Many people have pinworms and don't have any symptoms at all.
The most common symptom of pinworms is itching around the anus. It is worse at night when the female worm deposits her eggs on the person infected. This can lead to difficulty getting a good night's sleep. This intense itching is felt to be due to an inflammatory response to the adult worm and her eggs in the perianal tissue. If severe scratching occurs, the skin may break down and allow development of a secondary bacterial infection.
Pinworms can rarely migrate into the vagina or urinary tract causing irritation in these regions. Intense itching is again the prominent complaint. This location of infection is less common than the perianal region, and the infection usually goes away on its own. Case reports of E. vermicularis migration into the internal female reproductive tract have been reported. These infections are very rare.
Pinworms do not cause abdominal pain, bloody bowel movements, fevers, or poor appetite. If the person has any of these signs or symptoms, they may have a more serious condition and should call a doctor or visit the hospital's emergency department. Adult pinworms have been found in inflamed appendices removed at operation; however, whether the pinworm infection was the cause of appendicitis is controversial.