Pinworms are among the most common worm diseases in European countries. Infestation occurs mainly in children between the ages of four and eleven, but can also affect adults.
Infection usually occurs when infectious worm eggs are ingested and swallowed. In almost two thirds of the cases, the first symptoms appear about two to six weeks later. Pinworms only occur in humans – animals are not affected by the parasites.
Typical sign: nocturnal itching in the anal area
Typical of pinworms is severe itching in the anal area, which occurs especially at night when the body is at rest. The itching can make it difficult to sleep through the night and thus cause other symptoms.
The nocturnal itching on the buttocks occurs because the female pinworms migrate from the intestine towards the anus at night to lay their eggs in the skin folds of the anal area. Every now and then, the worms, which are around nine to twelve millimeters long and often very mobile, are still visible on the anus or on the stool even shortly after waking up. The pinworm eggs, on the other hand, are so small that they cannot be seen with the naked eye.
Due to the disturbed sleep at night, many sufferers are tired during the day and have problems concentrating. Children also often appear irritable and restless during the day due to the itching-related sleep problems. Smaller children may indicate their symptoms by sliding on the floor on their buttocks or by wriggling their legs a lot. Some children with pinworm infestations may start weeing their beds again at night.
The nocturnal itching on the buttocks is often so pronounced that it is difficult not to give in to it. Small children in particular scratch their anal area when they have pinworms (often unnoticed while they are sleeping). This can perpetuate an infestation if the fingers are later placed in the mouth. Because the eggs stick very well, even on the fingers and under the fingernails.
It is not uncommon for scratching to also lead to (sometimes significant) skin injuries on the anus. These can provide an entry point for bacteria. In some cases, pinworms result in eczema, which is accompanied by redness and a feeling of warmth, or accumulations of pus (abscesses) in the anal area.
Rare symptoms of pinworm infestation
In the event of an infestation, the adult pinworms live in the large intestine until the end of their life cycle – usually there are a few to several hundred specimens. Larger amounts are often found in certain sections in particular, namely in the appendix, appendix and colon. A large number of pinworms in the intestine can, in rare cases, lead to gastrointestinal problems and symptoms such as abdominal pain, nausea, vomiting, constipation or watery diarrhea. It is not yet clear to what extent they could possibly play a role in appendicitis.
In very rare cases, it can also happen that the pinworms in girls or women migrate from the anal area to the genital area – i.e. to the outer pubic area (vulva) or also to the vagina (vagina) – and cause symptoms such as inflammation and itching there. Under certain circumstances, urinary tract infections can also be related to a pinworm infestation if the worms get from the intestine into the genital area and carry intestinal bacteria there.
Pinworms: Symptoms do not always appear
In more than a third of the cases, pinworms cause no or only a few symptoms, so that an infestation can go unnoticed. If there is no itching in the anal area, the risk of self-infection is lower, provided there is sufficient hand hygiene and hands are washed, especially after defecation.
The pinworms may then disappear of their own accord after a few weeks as soon as they have completed their life cycle: Female specimens live on average for around 100 days, male specimens die shortly after fertilization. However, a proven infestation with pinworms should be treated medically.