Hi, many thanks for the query!
As you say you sometimes see white worms in anal region, it is
"Enterobius Vermicularis" (Pinworm), typically causing perianal itching.
If you are infected, the eggs on the tape will be visible under a microscope. The tape method should be conducted on 3 consecutive mornings right after you wake up & before you do any washing.
Since anal itching is there, the third option for diagnosis is analyzing samples from under fingernails under a microscope.
Since pinworm eggs & worms are often sparse in stool, examining stool samples is not recommended. Serologic tests are not available for diagnosing pinworm infections.
Get physically examined by your doctor once.
The medications used for the treatment of pinworm are mebendazole,
pyrantel pamoate, and albendazole. All three of these drugs are to be given in 1 dose at first and then another single dose 2 weeks later. Take it with your doctor's opinion.
It is recommended that all household members be treated at the same time.
Washing your hands with soap and warm water after using the toilet, changing diapers, and before handling food is the most successful way to prevent pinworm infection.
You should also cut fingernails regularly, and avoid biting the nails & scratching around the anus. Frequent changing of underclothes and bed linens first thing in the morning is advisable, also these items should not be shaken and carefully placed into a washer & laundered in hot water followed by a hot dryer to kill any eggs that may be there.
Wish you a good health.
Take care.
Regards.