Hello from JustAnswer.
Did the doctor order a test for threadworms?
What medicine did you get from the doctor?
I had asked for some further information and have not heard back.
It is true that threadworms are a common cause of anal itching, but if you were given a medicine that usually clears threadworms, the first issue is trying to establish a more definitive diagnosis. If the doctor ordered a test that showed threadworms, then the diagnosis is well established. If there has not yet been a firm diagnosis, there is a way to try to establish the diagnosis without seeing the doctor. Threadworms are usually not visible when examining the stool. However, the diagnosis may be able to be made if you have a family member that can visually look at the anus in the middle of the night. The threadworms exit the anus in the middle of the night and lay eggs on the perianal skin and having someone look at the anus the middle of the night may be able to identify the threadworms by the movement of the small, thin worms.
If the diagnosis is firmly established, then the next step would be the use of a different medicine, which is the primary reason that I asked which medicine has been tried. There are several medicines that can be used for threadworms, but the most common are mebendazole and pyrantel pamoate. So, if you have already been tried on one of these medicines, it would be reasonable to try the other
If I can provide any additional information, please let me know.