Anal itching – Pruritus ani

Anal itching
Intense anal itching is one of the commonest complaints confronted in a colorectal office and is one of the most challenging entity regarding patient satisfaction.

Because of moisture and warmth caused most often by long sitting period (in front of the computer) it is easily irritated. Some feeding habits like sodas and spicy food may aggravate the condition though pH disbalance of the perianal skin, as well as anal or vaginal discharge. This makes it difficult keep the area round the anus clean and dry.

When the anal region becomes irritated, scratching is a natural reaction. Intensive and repeated scratching, however, will finally damage the skin furthermore prompting to scratch – the itch/scratch vicious cycle is on its way.

Ointments and creams can cause further problems by causing allergic reaction.

Although it is very unpleasant, anal itching seldom means anything serious but should be assessed for underlying diseases if the symptoms persist.

Causes of anal itching
Anal itching is not a disease but a symptom. Although in some cases there is no obvious reasons, most have an underlying disease causing excessive moisture in the perianal region. Some of the most important discharge producing lesions are:

– Anal fissure
– Anal fistula
– Anal papillomata
– Condylomata accuminata

Excessive sweating, often combined in warm weather with rough non-cotton underpants

Lack of anal cleanliness. Poor hygiene can be responsible for anal itching as well as excessive cleaning,

Faecal leakage can lead to itching around the anus.

Pre-moistened toilet tissues (wipes) can sometimes cause anal irritation. The reason is probably perfume, alcohol or a preservative in the wipes. Only use baby tissue which do not contain aggressive chemical agents.

Sensitivities and allergies to other chemicals, such as bath oils and perfumed soaps, may be responsible.

Ointments and creams are notorious causes of anal itching. If you have itching, it is a natural reaction to buy an anaesthetic gel for the anal area. Most of these are labelled ‘for haemorrhoids’ and contain lignocaine, tetracaine, cinchocaine, pramocaine or benzocaine with other ingredients. At first they help, but then the itching may return because you have become sensitive to one of the ingredients in the cream or ointment and they are keeping the area moist. Do not use them for more than 1 week.

Perianal dermatitis due to psoriasis and eczema can affect the skin round the anus and cause itching. Piles can sometimes be itchy, partly because of the slimy discharge they produce.

Fungal infections, similar to thrush or athlete’s foot, are another common cause. Fungi love warm, damp and damaged skin, so if you have an itchy anus for any reason and then damage the skin by scratching, fungi can take hold and make it worse.

Sexually transmitted infections are what many people worry about, but are not usually the reason.
• Genital warts (vulva or penis), caused by papillomavirus, thrive in warm, moist conditions such as the skin near the anus and can be very itchy.
• Genital herpes (caused by herpes virus) can also infect the anus, and causes itching just before the sores appear and also during the healing stage.
Both these viruses are easily transferred to the anal skin on the fingers, and can therefore occur round the anus in anyone. The anus may be the only site of infection; the fact that you do not have genital warts or herpes elsewhere does not rule them out.

Threadworms (pinworms) are tiny worms, about 13 mm long, which live in the lower part of the bowel. They are very common – an estimated 40 million cases in the USA alone. The female worms creep out of the anus at night – how they know it is night, and why they come out only at night, is a mystery. They lay thousands of eggs on the skin of the anus, causing intense itching at night. When you scratch, the eggs lodge under your fingernails, and it is easy to transfer them to your mouth and reinfect your gut by swallowing the eggs.

Certain foods can irritate the anus during defecation. Beer and curry are obvious examples. Some people find that citrus fruits, grapes, tomatoes, coffee or tea can cause problems.

Anxiety tends to make the brain hyper-alert to body feelings that we may otherwise be able to ignore. If you are going through an anxious period, a symptom such as itching can become magnified.

Anal sexual practice. Some enjoy some form erotic pleasure from scratching the itchy area, which may irritate more.
How you can help yourself
• Wash the anal area after you have had your bowels open, but not more than three times in a day, using an unperfumed soap and water. Some doctors recommend using aqueous cream (available from pharmacies) as a cleanser. Apply the cream, massage it gently over the area and then rinse off. If you are somewhere where you cannot wash, clean the area with wet tissues (but not with pre-moistened wipes). If you use shower gel to wash your body, make sure you rinse it off very thoroughly so that none remains between the buttocks.
• Dab gently with a soft towel to dry – do not rub. If drying is difficult, use a hairdryer on cool setting.
• Do not put any disinfectant on the skin or in the bath water – this can irritate the skin. Do not use bubble bath – the perfume can irritate. Instead, put a handful of kitchen salt in your bath.
• Keep a cotton-wool ball, dusted with powder, against the anus, inside your underpants or knickers. Use baby powder (not perfumed talcum powder) to dust it. Change it each time you wash.
• Wear loose cotton underwear. Avoid tights and elastic ‘shapewear’ underwear, because they encourage sweating and moistness in the anal area. Avoid anything that keeps the buttocks close together.
• Do not use biological (enzyme) washing powders for your underwear, or perfumed fabric softeners. Instead, use a detergent labelled ‘for sensitive skin’.
• Do not scratch. If you scratch, you damage the skin more and then you itch more. If you feel you really must scratch, try pinching the skin near the anus between your thumb and forefinger through your clothing; this is less damaging than actual scratching. People often scratch at night and do not realize they are doing so. If you think you might be scratching at night, talk to your doctor about taking an antihistamine, keep your fingernails short, wear cotton gloves at night for a while and ask your doctor to check for threadworms.
• Do not use any greasy creams (such as Vaseline) on the area. Greasy creams keep the skin soggy and make the problem worse. Zinc oxide cream (from pharmacies) can be soothing if the skin has been damaged by scratching.
• Be very cautious about anaesthetic creams or ointments. Sometimes they can help by relieving the itch/scratch cycle, but use them only for a short period (about a week).
• Similarly, be very cautious about steroid creams. In the UK, it is possible to buy weak steroid cream (containing hydrocortisone 1% or less) from pharmacies. In the short-term, the steroid reduces inflammation and therefore relieves itching but, in the long-term, it can make the skin thinner and worsen the problem. Resist the temptation to keep on using a steroid cream. Use it for just 1 week, then throw the tube away.
• Try witch hazel – an old-fashioned remedy available from pharmacies. Dab it on twice a day, but stop immediately if it seems to be making the problem worse instead of better.
• Dr James Le Fanu has a column in the Daily Telegraph that acts as a forum for readers’ solutions to health problems. Readers have reported that the inside of a banana skin can relieve itchy skin, including anal itching.
• Feel round the anus for lumps. This may not be easy, because the skin round the anus is normally puckered. A lump might be a wart, a pile or a skin tag alongside an anal fissure.
• Avoid foods that cause excessive bloating
How your doctor can help
If you are anxious about being examined by your doctor, look at the section on seeing your doctor about an anal problem. Your doctor can check to see whether you have any conditions such as piles (haemorrhoids), fissure, warts, psoriasis, eczema, fungal infections or other infections that need treatment.
• If you scratch at night, an antihistamine taken before you go to bed can help. Antihistamines relieve itching and some also tend to make you drowsy.
• Discuss with your doctor whether you might have threadworms (pinworms). They look like small threads of slow-moving white cotton. These can be eliminated with mebendazole or piperazine. The treatment has to be repeated after 14 days, because the eggs can persist for this length of time in the environment (NHS MeRec Bulletin 2008;18:11–13). The other members of your household will also need to be treated, and you should also wash your hands and scrub your nails before eating and after each visit to the lavatory, and wash the anal area in the morning to get rid of any eggs deposited during the night.
• An ointment containing a chemical found in chilli peppers (capsaicin) is an effective treatment for very troublesome anal itching (Gut 2003;52:1233–5), but the researchers used a special very dilute ointment (0.006%) that is not generally available.
• If nothing helps, your doctor might consider referring you to a specialist for injection of a chemical called methylene blue into the anal area. So far, research has involved only a small number of patients, but the itching improved in most patients and disappeared completely in half (Colorectal Disease 2009;11:282–7). More research is awaited to find out how long the relief will last.

Further reading Praxis Sievering