Often, pinworm infection does not cause any symptoms. If there is, they are light:

• itching (anal or vaginal area) typically in the evening and at night;
• restlessness, nervousness, insomnia (because of itching);
• diarrhea;
• abdominal pain: they are present in 20% of people harboring pinworms and are due to chronic inflammation of the intestine (which is also responsible for diarrhea);
• nausea or vomiting (rare);
• vulvite¹.