What are they
Pinworm infection, also called oxyuriasis or enterobiasis, is one of the most common intestinal parasites in humans. It mainly affects children, about 10%.
The ease of contagion at an early age is mainly due to an immune system that is not yet fully mature and to the lack of predisposition to observe hygienic-sanitary rules more typical of adulthood.
Pinworms are small vermicelli belonging to the group of Nematodes, shaped like cylindrical filaments, white in color, about one centimeter long, thin and mobile.
The main intestinal parasites are Enterobius vermicularis and Enterobius gregorii: they live exclusively in the human intestine, in particular in the large intestine and rectal ampoule, and are characterized by a direct development cycle, that is, devoid of intermediate hosts.
Routes of contagion
Transmission can occur in different ways, although the most frequent is through the fecal-oral route, i.e. with the accidental ingestion of microscopic pinworm eggs found in the environment, in food or in everyday objects given their ability to survive up to 2-3 weeks once they have been expelled from the previous host.
Airway can also be a mode of transmission due to the small size and low weight of the eggs. Being easily lifted from surfaces, for example by slamming sheets, they can enter the body through inspiration and, subsequently swallowing, reach the intestinal site. The fecal one, on the other hand, is not to be considered a way of contagion as the eggs are not eliminated with the faeces.
Once they reach the small intestine, the eggs hatch releasing larvae which, migrating to the colon, mature in a few weeks. Female pinworms, in addition to being larger, are also characterized by a longer survival than males, reaching 13 weeks against 7 weeks for the opposite sex. In fact, adult males die immediately after fertilizing females by the action of specific intestinal enzymes, while females, adhering to the intestinal mucosa from which they draw food for the maturation of the eggs they carry, reach the last part of the intestine, the colon.
After having detached from the wall, especially at night and early in the morning, they come out of the anus and, although they also die from dehydration in contact with the air in less than half an hour, they deposit thousands of eggs in the and perianal area, from 11,000 to 16,000 for each female specimen. The eggs, requiring a maturation period ranging from 4 to 6 hours, are potentially able to re-infect the host already in the morning.
The eggs, invisible to the naked eye due to their very small size, are released into the external environment only after about 4 or 5 weeks from the initial development of the infection.
When pinworms lay eggs anally and perianally, the baby feels a sensation of intense itching and will easily scratch.
Microscopic residues of feces are thus deposited on the child’s hands and, touching everyday objects (toys, pencils, as well as sheets, towels and undergarments) contaminates them with eggs.
If another child, or an adult, touches the same objects and brings his hands to his mouth, he in turn ingests the eggs starting a new reproductive cycle.
Among the factors that facilitate contagion, in addition to close contact with an already affected subject and young age, we also find overcrowding and, in general, poor hygiene rules.
Pinworms infect only humans and not pets such as dogs or cats, which can however represent an indirect transmission route by transporting eggs still alive into the hair.
Symptoms
It can sometimes be asymptomatic, considering how the extent and manifestation of symptoms is to be linked to the site and importance of the infestation itself. Especially in the initial stages, therefore, it may not be felt by the host.
However, the main symptoms remain itching and irritation at the anal level, which leads pediatricians to suspect pinworms if a child scratches his ass often.
itching is due to the movement of female pinworms inside the intestine and is therefore more intense at night and early in the morning. Girls sometimes also experience vulvar itching and may experience vaginitis.
In some cases, especially in children, restlessness, irritability, insomnia, teeth grinding (bruxism), loss of appetite and enuresis (involuntary loss of urine) also appear.
The complications, although not frequent, concern the appearance of skin lesions due to the intense act of scratching, resulting in secondary bacterial infections (such as dermatitis or folliculitis that can also extend to the anterior genitalia). Even rarer are systemic infestations found through blood tests, which present an excessive increase in white blood cells.
Diagnosis
In some cases the diagnosis is easy, because pinworms can be observed on the stool or even in the orifice.
In many cases, however, more specific procedures must be used, such as the scotch test, the sampling of the sample using a cotton stick and the examination of the stool.
The scotch test is performed in the morning as soon as you get up, before going to the bathroom, applying common adhesive tape (as long as it is transparent) on the opening.
In this way the eggs remain attached to the adhesive tape, which must be applied on a microscope slide being careful to avoid the formation of air bubbles.
There is not always a clear and certain diagnosis the first time the scotch test is performed and, in case of negativity, the operation is usually performed for three or four consecutive days. At this point everything is taken to a diagnostic center.
Since the itching in this area could be due to other disorders, such as candidiasis, it is important to consider all hypotheses.
Therapy and practical advice
There are some drugs, called anthelmintic or antiparasitic, that are able to eradicate pinworms.
The most suitable drug for both children and adults is mebendazole for oral administration. Its mechanism of action is simple and involves blocking the use of glucose by worms which, finding themselves deprived of their main source of energy and nourishment, slowly meet death. It requires a prescription and should be given to children over two years of age as a single or double dose (two weeks apart). It is contraindicated in pregnancy and among the main side effects we find stomach pain, diarrhea, erythema and flatulence.
In addition to mebendazole, always to be taken by mouth, albendazole are also available, with an action similar to the first, and pirantel pamoate, which instead induces motor paralysis with consequent detachment from the intestinal wall and expulsion with feces.
Often, pharmacological treatment alone is not able to completely eliminate pinworms and it is therefore important to focus also on the prevention of further infections and on the complete disinfestation of the already affected host.
Here are the practical tips recommended by doctors:
| What to do | What to avoid |
|---|---|
| Wash your hands frequently and brush well with soap and water of the baby to avoid self-re-infestation, cleaning carefully even under the nails and having the foresight to keep them short | Share belongings |
| Change underwear, sheets, towels and, in the case of children, diapers more frequently than usual washing at high temperatures (60 ° C) even clothing, as the heat is able to kill the eggs | Raise dust, as it is a possible source of airborne transmission (it is therefore advisable to use a damp cloth during cleaning) |
| Practice upon waking up a correct and accurate intimate hygiene, even in the folds, to eliminate the eggs deposited during the night | |
| Wash and sterilize toys or temporarily replace the most used ones while waiting for the eggs to die | |
| Treat family members and others potentially at risk at the same time to completely eradicate the possibility of infestation | |
| Continue with these practices even during drug treatment |
Then there are some natural remedies that, by tradition, boast a certain effectiveness, but which in no case should replace the consultation with the doctor and the intake of specific drugs.
Among them, the most common is the morning and fasting ingestion of water with chopped and previously macerated garlic. Like garlic, fennel, onion, strawberries, lemon and pineapple juice also seem to have anthelmintic activity.
There are also some plants with a vermifuge action such as pomegranate bark, wormwood and tansy, whose use must however be avoided during pregnancy and in young children given their potential toxicity.
The use of natural laxatives, such as plums, can facilitate the elimination of the worm itself through the faeces.
Finally, it is advisable to apply a soothing and moisturizing cream to prevent itching in the area around the anus.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
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