Tight clothing, nylon underwear, and
skin folds resulting from obesity
may trap moisture in the area.
Certain foods can produce enzymes that are irritating to the skin when stool is passed. The more common ones are products containing caffeine (coffee, tea, colas, and chocolate), spicy foods, dairy products, beer, citrus fruits, tomatoes, and nuts.
Dyed or scented toilet paper, soaps, and laundry detergent may cause the irritation.