The itching usually happens at night, when a female worm lays eggs around the anus. You may see them in your underwear or in the toilet after a bowel movement. They look like tiny pieces of white.

Harvard Medical School: “Anal Itch (Pruritus Ani).” Cleveland Clinic: “Pruritus Ani (Anal Itching),” “7 Best and Worst Home Remedies for Your Hemorrhoids,” “Anal Fistula.”

It may be seen with primary biliary cholangitis (previously referred to as primary biliary cirrhosis), primary sclerosing cholangitis, intrahepatic cholestasis of pregnancy, biliary obstruction, chronic viral hepatitis, cirrhosis, prolonged drug-induced cholestasis, and inherited cholestasis syndromes (eg, progressive familial intrahepatic chole.