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Enterobiasis
Last reviewed: 05.07.2025
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Enterobiasis (Latin: enterobiosis; English: enterobiasis, oxyuriasis) is an anthropozoonotic contagious helminthiasis of humans, characterized by perianal itching and intestinal disorders.
ICD-10 code
B80. Enterobiasis.
Epidemiology of enterobiasis
The source of infection is only an infected person. The mechanism of infection is fecal-oral. The main factor of transmission of enterobiasis is hands contaminated with pinworm eggs, as well as household items and toys. Pinworm eggs are found on the floor, carpets, chamber pots, etc. Scratching due to severe itching in the perianal area contributes to the accumulation of eggs under the nails, where the larvae complete their development to the invasive state. Retroinvasion is sometimes possible, when pinworm eggs mature in the anogenital area, the larvae crawl back into the intestines and mature there. Contagiousness is very high. Despite the short lifespan of pinworms, due to the possibility of frequent repeated infections, enterobiasis can last for years. Enterobiasis is widespread, mainly in countries with a temperate climate. The intensity of the lesion largely depends on the sanitary culture of the population. Enterobiasis mainly affects children of preschool and primary school age. According to WHO estimates, 350 million people in the world are affected by this helminthiasis; in Ukraine, enterobiasis is the most common of helminthiasis.
What causes enterobiasis?
Enterobiasis is caused by pinworms (Enterobius vermictdaris), belonging to the type Nemathelminthes, class Nematoda, order Rhabditida, family Oxyuridae. The body of adult helminths is spindle-shaped: the length of the female is 9-12 mm, the male - 3-5 mm. The tail end of the female is pointed, while that of the male is spirally bent to the ventral side. The eggs are asymmetrical, oblong, measuring 0.05 x 0.02 mm: their shell is transparent, with a double contour. A mature female parasitizes in the cecum. At night, when the sphincter relaxes, she independently exits through the anus and lays from 5,000 to 15,000 eggs on the perianal folds, after which she dies. The embryo contained in the egg develops into an invasive larva within 4-5 hours. The eggs, which are relatively resistant to drying, contaminate underwear and bed linen, where they remain invasive for up to 2-3 weeks. A feature of the life cycle of E. vermicularis is the absence of a migration phase and low immunogenicity. The life span of pinworms from the moment of infection until the emergence of mature females for egg laying is about 30 days.
Pathogenesis of enterobiasis
Pinworms cause mechanical damage when attached to the intestinal mucosa, especially severely injuring females with their long and sharp tail end. Mechanical irritation and the action of the helminths' waste products cause itching of the skin in the perianal area. Pinworms sometimes immerse themselves in the thickness of the intestinal mucosa, with granulomas forming around them. As a result of the introduction of pathogenic microorganisms deep into the tissues, pinworms can contribute to the development of typhlitis, appendicitis, and the helminths themselves, penetrating the vermiform appendix, can cause appendicular colic. Ectopic migration of pinworms can cause vaginitis, endometritis, and salpingitis in girls. There are cases where helminths were found in the abdominal organs when the integrity of the intestinal wall was compromised, caused by other diseases, against which the invasion occurred.
Symptoms of enterobiasis
Symptoms of enterobiasis are more pronounced in children, in adults helminthiasis can be asymptomatic or subclinical. The most common symptom is itching in the anal area. With low invasion, itching occurs periodically, as the next generations of female pinworms mature. Itching appears in the evening or at night, when the helminths crawl out of the anus. With intense invasion, itching and burning become constant and debilitating, spreading to the perineum and genitals. Long-term and intense scratching of itchy areas (around the anus, in the perineum, labia) contributes to lichenification of the skin and the development of eczematous dermatitis, pyoderma, sphincteritis, and sometimes paraproctitis. Enterobiasis in many cases is a "trigger factor" for itchy dermatoses of the anogenital area. Also, patients, especially children, note such symptoms of enterobiasis as irritability, poor sleep, increased fatigue; fainting, epileptiform seizures, and nocturnal enuresis are registered in children. With massive invasion, gastrointestinal disorders occur: pain and rumbling in the abdomen, flatulence, nausea, vomiting, constipation or diarrhea, sometimes with an admixture of mucus. When pinworms penetrate the appendix, symptoms of acute abdomen may appear, in such cases, patients undergo surgery: catarrhal changes are found in the removed appendix, eggs and adult helminths are found in its lumen and the thickness of the mucous membrane.
Diagnosis of enterobiasis
Adult helminths are sometimes found on the surface of feces. Diagnosis of enterobiasis consists of identifying pinworm eggs - examination of the material (scraping) obtained from the perianal folds using a tampon, spatula, transparent adhesive tape, the imprint method using glass eye sticks with an adhesive layer according to Rabinovich. At least three repeated studies are recommended to completely exclude the possibility of invasion.
Differential diagnosis of enterobiasis
Differential diagnostics of enterobiasis is carried out with other diseases that manifest as perianal itching: hemorrhoids, diseases of the rectum (ulcerative, neoblastic lesions), diabetes mellitus, neurodermatitis, etc.
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Indications for consultation with other specialists
Consultations with a gynecologist are necessary for itching in the genital area in women, and consultations with a surgeon are necessary for abdominal pain.
Indications for hospitalization
Antiparasitic treatment of enterobiasis does not require hospitalization of patients.
What do need to examine?
What tests are needed?
Who to contact?
Treatment of enterobiasis
Treatment of enterobiasis consists of prescribing medications. The drugs of choice are albendazole, mebendazole, carbendacim: pyrantel is an alternative.
Albendazole is prescribed orally: adults 400 mg once, children over 2 years old - 5 mg/kg once; repeated administration at the same dose after 2 weeks.
Mebendazole orally 10 mg/kg once; repeat administration at the same dose after 2 weeks.
Carbendacim orally 10 mg ; kg in three doses during 1 day; repeated dose at the same dose after 2 weeks.
Pyrantel orally 5-10 mg/kg once; repeat administration at the same dose after 2 weeks.
Repeated treatment of enterobiasis with the selected anthelmintic drug is carried out after 2 weeks and is due to the fact that due to the possibility of re- and superinvasions, one course may not have the desired effect. Prerequisites for successful deworming for enterobiasis are simultaneous treatment of all family members (children's group) and strict adherence to the hygienic regime to prevent re-infection. Before treatment, a thorough wet cleaning of the room is carried out. It is recommended to wash the sick child (shower), change underwear before going to bed, put on panties that fit tightly around the hips. In the morning, the child must be washed, change underwear, replace bed linen or iron it with a hot iron. Wet cleaning of the room should be carried out daily. The same is done during the repeated course of treatment.
Monitoring the effectiveness of treatment using the above parasitological methods is carried out 15 days after the full completion of the course of treatment.
More information of the treatment
How to prevent enterobiasis?
Enterobiasis can be prevented by identifying the source of the invasion and eliminating the routes of transmission of the pathogen. For this purpose, once a year (after the summer period when forming a children's group or according to epidemiological indications), scheduled preventive examinations of children and service personnel are carried out. Children with enterobiasis are suspended from attending preschool and educational institutions during treatment and follow-up examinations. If 20% or more of those infected with enterobiasis are detected during scheduled preventive examinations in organized groups, in accordance with regulatory documents, all children and staff are given antihelminthic treatment at the same time (twice with an interval of 2 weeks). In the center of enterobiasis, it is necessary to strictly maintain the cleanliness of the home, office, and school premises. Persons in contact with patients must maintain cleanliness of the body, clothes, wash their hands before eating and after using the toilet.
Prognosis for enterobiasis
Enterobiasis usually has a favorable prognosis.