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Worms are the commonest cause of anal itch. 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, Crohnâs and food intolerance should also be looked into. Anal fissures, hemorrhoids, threadworms can all cause anal itch.
Itch can also be due to irritants like synthetic fiber, toiletries or fungal infection. Genital warts and sores of herpes should also be ruled out. Eczema, dermatitis and fungal infection can also cause this. You need to consult a skin specialist for confirmed diagnosis. Your PCP too can help run basic tests like stool examination and STD swab tests for herpes and genital warts. Hope this helps. Take care!