Pruritus ani is the medical term for rectal itch. The delicate skin of the anus, the outlet of the rectum, is subject to irritation and itching. Scratching only makes things worse and can lead to secondary infection. While it's natural to assume that better hygiene can solve the problem, efforts to cleanse and scrub this area may cause fissures, drying and skin reactions that ultimately cause more distress. Itching is a response to inflammation; there are many possible causes of rectal inflammation.
Hemorrhoids
Veins around the anus and inside the rectum can become distended from poor circulation and pressure. Pregnancy, constipation, obesity and sitting for long periods of time are common causes. According to the American Academy of Family Physicians, external hemorrhoids involve the veins outside the anus; they may swell and be itchy or painful. Internal hemorrhoids may bleed painlessly and drain mucus that causes itching. A high fiber diet, increased fluids, regular exercise, frequent tub baths and over-the-counter remedies can bring relief in most cases; hemorrhoids that require more aggressive treatment may benefit from surgery.
Fungal Infection
Also known as candidiasis, an overgrowth of yeast organisms may occur as the result of antibiotic medications that kill off competing "friendly" bacteria, or probiotics. Such fungal infections are intensely itchy, and the Mayo Clinic reports they are more common in women. Diabetics and those who have a diet high in sugar and refined starches are most at risk. Wear cotton underwear and wash hands to prevent the spread of candida to other warm, moist areas of the body. Treatment with over-the-counter anti-fungal creams and a healthy diet which includes fermented foods (such as yogurt and kefir) or probiotic supplements is usually effective.
Pinworms
When children have rectal itch it could be an indication of parasites. Pinworms, or threadworms, live in the rectum. The females come out at night and lay eggs around the anus, which causes inflammation and itching. According to the National Institutes of Health, the eggs are swallowed by fecal-oral contamination, usually among young children, and are not spread by pets. Worms may be visible near the anus while the child is sleeping, or eggs can be lifted with scotch tape upon awakening and examined under a microscope. The eggs can live outside the body for up to three weeks. Hand washing, with careful attention to fingernails, helps prevent the spread of these common parasites. Pinworms are treated with medication and laundering of the infected person's bedding in hot water.
Chemicals
Some soaps, perfumes, lotions or scented toilet paper can cause irritation and anal itching. Chemicals in foods may cause inflammation when they pass through the rectum. The Mayo Clinic lists hot peppers, chocolate, alcohol, tomatoes, nuts and popcorn as common sources. A food allergy or intolerance may produce anal itching either when the food comes in contact with mucus membranes or as a result of diarrhea. Common food allergens include milk, eggs, soy, wheat, corn, shellfish and peanuts. Allergic reactions may be delayed; an elimination diet and diary is the best way to pinpoint offending foods.
