Worms are the commonest cause
of anal itch. Scratching repeatedly can cause
sores. However, this has been ruled out in your case.
Itchy anus can also be due to undigested food like citrus fruits, grapes, certain spices, tomatoes, certain medicines like antibiotics and laxatives and certain drinks like beer, milk, tea, or coffee. IBS, Crohn’s and food intolerance should also be looked into. Anal fissures, hemorrhoids, threadworms can all cause anal itch.