You can know if you have worms by observing certain symptoms and through specific diagnostic tests. The most common symptom of threadworms, the most frequent worm infection, is an itchy bottom, especially at night when the worms lay eggs around the anus. You may also see small white thread-like worms in stools or around the anus. In children, irritability, poor sleep, and poor appetite can also be signs. Other symptoms of worm infections may include diarrhea, abdominal pain, tiredness, weight loss, anemia, red itchy rashes shaped like worms on the skin, and in some cases, the appearance of worm segments or eggs in stool. Worms that migrate under the skin can cause red or pink curving tracks with intense itching. Diagnosis is often made by identifying the worms or their eggs in stool samples or by specific tests such as the "sticky tape test" (pressing clear sticky tape on the anus in the morning to detect eggs). Blood tests, imaging (MRI or CT scans), and clinical symptoms can also aid diagnosis. If you experience symptoms like severe or persistent diarrhea, abdominal pain, visible worms in stool, itchy rash, unexplained weight loss, or severe fatigue, it is important to see a doctor for evaluation and testing to confirm the presence of worms and receive appropriate treatment.