Enterobiasis or Aharqs
Description
The pinworm, or Enterobius vermicularis, is a small parasitic worm that lives inside the large intestine in humans. Measuring only 3mm to 10mm in length, it causes intense anal itching, especially at night.
Pinworms usually infest people who attend crowded schools, who live in large family clusters or in unsanitary conditions, or those who eat undercooked food. Moreover, they are not necessarily a sign of poor personal hygiene. They are very often found in institutional settings such as dormitories, psychiatric hospitals and foster homes.
Pinworms are the most common parasite in North American children and it is estimated that one-third of Canadian children will have pinworms at some point in their lives.
Causes
At night, the female leaves her focus of infection, which is located in the lower part of the digestive tract. Coming out of the rectum, she lays her eggs in the folds of the skin around the anus. The eggs are coated in a gelatinous and sticky substance which, with the wriggling of the female, causes intense itching. The eggs are transferred to the fingers either directly by scratching the anal area or through clothing and bedding. They can then be taken to the mouth and swallowed, or passed on to other people by touch.
Since the eggs survive for up to 20 days, clothing and bedding provide viable environments for them. If these tissues are shaken, the eggs may be dispersed in the air and swallowed directly. Once swallowed, they will hatch in the intestine and reach their adult worm form in 2 to 6 weeks. Adult worms can live for about 3 months, and females lay up to 10,000 eggs in their lifetime.
Pinworm eggs attached to the perianal surface hatch after 6 hours and emerging larvae return to the anus, where they reside to mature in the large intestine. Those that fall into clothing or bedding can survive up to 3 weeks at room temperature waiting for helping hands to carry them to the mouth. Humans are the only natural hosts of pinworms.
Symptoms and Complications
Pinworms mainly affect children between 5 and 10 years old. Most of them have no symptoms other than itchy anus, which sometimes becomes raw from scratching. Pinworm infection is rare in children under 2 years of age. In girls, they can cause itching and irritation in the vagina (vaginitis).
In severe cases, it can cause weight loss, nervousness, irritability and loss of appetite. In very rare cases, pinworms can block the appendix and cause appendicitis.
Diagnostic
To make a diagnosis of pinworm, the female worm or eggs must be found. To find the female, examine the anal area of the affected person at night with a flashlight. The person should have slept at least one hour before the exam. The white female worm is about the size of a fine hair and only 10mm long (males are about 3mm), but it wiggles and is easily seen with the naked eye. All the worms collected must be deposited in alcohol or vinegar to be taken to the clinic or to the doctor who will establish the diagnosis.
Another collection method is to use a sticky tape to collect any eggs or worms left around the anal area in the morning before washing and before passing stool. Simply pat the folds of skin around the anus with the adhesive side of the tape. The tape must then be folded back on itself, on its adhesive surface, and taken to the doctor. Eggs and worms stuck to the tape will be examined under a microscope. This test is sometimes repeated 3 times. Pinworms are sometimes visible in stool samples.
Treatment and Prevention
Pinworms cause no discomfort or discomfort other than anal itching, and treatment can cure the condition in most cases. The key is to break the 6-week reinfestation cycle by eliminating all live pinworms and preventing egg ingestion. The diagnosis must be confirmed before treatment with medication.
The drugs only destroy adult worms and have no effect on incubating eggs and larvae. The most prescribed drugs are mebendazole*, on prescription, and pyrantel, over the counter. Mebendazole and pyrantel are given in a single dose, repeated two weeks later to destroy any eggs that may have been ingested in the meantime .
Because the eggs spread rapidly, all occupants of thehome should take the medicine, even if they have no symptoms. Reinfection is common, as eggs continue to be present in feces for up to a week after treatment.
Machine washing of all bedding, clothing and toys is essential to destroy all eggs. Vaseline, anti-itch creams or ointments can relieve tingling in the anal area. Washing your hands frequently, especially after using the bathroom, after scratching, and before eating, and keeping fingernails short and clean reduces your chances of picking up pinworm eggs.
For the week following the treatment, all family members should wear cotton underwear washed in very hot water and detergent. These underwear should be changed twice a day. Children should wear closed nightwear or tight-fitting underwear to avoid hand contact and bedding contamination. Infected people should shower every morning to remove any eggs that may be present on the skin. Wash sleepwear, underwear and washcloths daily. Wash sheets often and avoid shaking bedding and sleepwear before washing.
All medicines have both a nonproprietary name (a generic name) and a brand or brand name. The brand is the name that a manufacturer chooses for its product (eg Tylenol®). The generic name is the name of the drug in medicine (eg acetaminophen). A medicine can have several brand names, but it has only one generic name. This article lists medications by their generic name. For information on a specific drug, consult our drug database. For more information on brand names, consult your doctor or pharmacist.
