Itchy Anus (Pruritus Ani)

Why the anus itches

The skin around the anus is thin, folded and often warm and damp. Tiny amounts of stool or mucus left on it are irritating, and scratching or vigorous cleaning damages the skin further. This creates an itch-scratch cycle: the more you scratch, the more inflamed the skin becomes and the more it itches. In about half of people no single cause is found, and this cycle is the main problem.

Common causes

Hygiene: too little or too much

• Leftover stool from incomplete wiping, loose stools or leaking hemorrhoids
• Over-cleaning with soap, scrubbing, scented wipes or harsh toilet paper, which strips protective oils
• Sweat and heat, tight synthetic underwear, obesity and long sitting

Diet

Some foods and drinks are linked with itching, possibly by loosening stool or relaxing the anal sphincter: coffee (including decaf), tea, cola, beer, wine, chocolate, citrus, tomatoes, spicy food and dairy. Cutting them out for 2 weeks and reintroducing one at a time can identify a trigger.

Anal conditions

• Hemorrhoids and skin tags that make cleaning harder and leak mucus
• Anal fissure, a small tear causing pain with bowel movements
• Anal fistula draining fluid
• Fecal leakage from weak sphincter muscles

Infections

• Pinworms: tiny white threadworms that lay eggs around the anus at night. Very common in children and spread through households. The itch is much worse at night.
• Yeast (candida): more likely with diabetes, antibiotics or steroid use. Red, moist skin with small spots at the edge.
• Fungal infections, scabies, bacterial infection with streptococcus in children (perianal strep, with bright red skin), and sexually transmitted infections such as herpes and warts.

Skin conditions

• Contact dermatitis from creams, wipes, perfumed products, latex or the ingredients in hemorrhoid creams. See contact dermatitis.
• Psoriasis: a smooth, red, well-defined patch in the cleft, often without scale.
• Eczema and lichen simplex from chronic scratching, with thickened skin.
• Lichen sclerosus: white, thin, fragile skin, often around the genitals too.

Rare causes

Anal cancer, precancerous changes (anal intraepithelial neoplasia) and Paget's disease of the skin can cause persistent itching with a patch or sore that does not heal. That is why itching that does not respond to treatment should be examined.

How doctors find the cause

A doctor will ask about bowel habits, cleaning routines, products used, diet, other skin problems and household members with itching. They will examine the skin and may do a gentle internal exam or look inside with a short scope (anoscopy). Tests can include:

• the tape test for pinworms: sticky tape pressed on the anus first thing in the morning, looked at under a microscope
• skin scrapings or swabs for yeast, fungus or bacteria
• patch testing for allergic contact dermatitis
• a skin biopsy for a patch that does not heal or looks unusual

How to stop anal itching

1. Clean gently. After a bowel movement, rinse with plain lukewarm water, using a shower head, bidet, or a squeeze bottle. If you use paper, dampen it with water. Avoid soap, scented wipes and scrubbing.
2. Dry thoroughly. Pat dry or use a hair dryer on a cool setting.
3. Protect the skin. Apply a thin layer of zinc oxide or petroleum jelly barrier cream.
4. Keep dry during the day. A small piece of cotton gauze or a cotton ball in the cleft absorbs moisture. Wear loose cotton underwear.
5. Stop scratching. Keep nails short and wear cotton gloves at night if you scratch in your sleep.
6. Firm up stool. A fiber supplement such as psyllium helps you wipe cleanly and reduces leakage.
7. Review your diet and try cutting out common trigger foods for 2 weeks.
8. Short-term hydrocortisone 1% cream twice a day for up to 1 to 2 weeks can break the itch-scratch cycle. Do not use it long term, as steroids thin the skin.

Treating specific causes

• Pinworms: an over-the-counter or prescription deworming medicine, usually for everyone in the household, repeated after 2 weeks, along with hand washing and laundering bedding.
• Yeast: an antifungal cream such as clotrimazole.
• Psoriasis, lichen sclerosus or eczema: prescription creams from a doctor or dermatologist.
• Hemorrhoids or fissure: fiber, fluids, and medical or surgical treatment if needed.

Frequently asked questions

Why is my anus itchy at night?

Warmth in bed makes skin itch more, and you scratch without realizing during sleep. Pinworms are a classic cause of night-time itching because the worms lay eggs around the anus at night. A tape test or a check by a doctor can confirm them.

Can wiping too much cause an itchy anus?

Yes. Over-cleaning with soap, scented wipes or dry toilet paper is one of the most common causes. It removes the skin's natural oils and irritates it. Rinsing with water and patting dry is better than vigorous wiping.

What cream is best for an itchy bottom?

A plain barrier cream with zinc oxide protects irritated skin. A 1% hydrocortisone cream used twice daily for a short period, up to 1 to 2 weeks, can calm inflammation. Avoid creams with fragrances, numbing agents or witch hazel, which can cause allergic reactions.

Is anal itching a sign of cancer?

Very rarely. Most anal itching is caused by hygiene, moisture or skin irritation. Get it checked if it lasts more than 3 weeks despite home care, or if there is bleeding, a lump, a sore that does not heal or a change in the skin color or texture.