Threadworms are also commonly known as pinworms. They are a common parasitic infection that can be picked up by ingesting soil or other substances contaminated with worm eggs. They are most common in children, typically picked up from playing outdoors. Threadworms or pinworms are not generally a serious medical problem. However, they can be very uncomfortable because the worms, which live in the colon, migrate out of the anus to lay their eggs on the skin surrounding the anus. This causes a sensation of extreme itchiness.
Unfortunately, threadworms cannot be treated at home. First, you will need your primary care doctor
to take a sample and examine it under the microscope to confirm the diagnosis. Second, the only effective treatment is an anti parasitic medication which you can only get by prescription from your doctor.
Additionally, threadworms are relatively uncommon in adults, so it is important to consider alternative diagnoses that might give you anal itching (I am assuming this is your symptom). For example, hemorrhoids
are a very common cause of anal itching in adults that your doctor can rule out for you.