Introduction 

Pruritus Ani is a common condition that is characterised by itching or irritation around the anal margin and results in chronic skin damage and secondary infection. There are many possible causes and these usually relate to problems within the anal canal but occasionally it may be caused by a variety of skin conditions. As the result of leakage of faecal material, or liquid mucus, from the anal canal onto the skin outside the anus, irritation occurs.

Usually patients have suffered for months or years before consulting a specialist and their condition has often been wrongly diagnosed or treated inappropriately. Most have tried a variety of topical ointments (containing steroids, alcohol, antibacterial or antifungal drugs) prescribed or otherwise before being seen.

In the main the condition causing the initial injury has abated and it is instead the now chronic skin condition that requires careful attention.

Symptoms of Pruritus (Itching)

• Itching and soreness of the skin of the anal margin
• Dampness of perianal skin
• Thickening and lumpiness of the perianal skin
• Difficulty keeping perianal skin clean
• Bleeding

Causes

Any condition that results in the presence of stool or mucus on the perianal skin for a prolonged period may lead to pruritus ani. This may be caused by –

• Inadequate fibre in the diet causing sticky poorly formed stools and the need to strain
• Skin tags
• Haemorrhoids (prolapsing or otherwise)
• Fistula in ano
• Mucosal or rectal prolapse
• Bowel polyps
• Skin conditions
• Medicines (both oral and applied locally)

Investigation

Should be carried out by a specialist surgeon in clinic and may involve history and examination as well as some form of bowel investigation. An endoscopy is usually performed at a later stage. The cause of the problem is usually obvious.

Treatment

Pruritus ani is difficult to treat and it may take many months of care and attention to improve the condition. After evaluation of the rectum and lower large bowel to ensure there are no underlying problems, such as those above requiring intervention, treatment is directed towards healing the damaged skin.

The management of the skin condition is multi-factorial and requires a combined approach to treat what may be considered to be nappy rash. With this in mind, it is crucially important that the skin of the perianal region is not exposed to any irritants that may cause further injury or prevent healing from occurring.

• All topical agents applied to the perianal region should be ceased immediately with the exception of barrier creams, such as Sudocrem and Drapolene (i.e. those to treat nappy rash). Specialist dermatological preparations may be used at a dermatologist’s discretion.

• The perianal region should be kept as clean as possible at all times using either a shower or bidet after evacuation of the bowels or, where not possible, the use of hypoallergenic wet wipes similar to those used for babies in nappies. (Should itching worsen after the use of wet wipes, they should be discontinued and instead water soaked cotton wool buds used to clean the perianal region). Ordinary toilet tissue of any kind should be avoided. The perianal area should be cleaned daily in the shower or bath but no soaps or detergents of any kind should be used to assist with this, water alone will suffice. It is very important to ensure that hair is not washed in the bath and that all bath salts and bubble baths are avoided.

• After washing, the perianal area may be dried by gentle patting with a soft towel or a hair dryer on a low heat setting. Baby talc may be used to keep an otherwise moist area dry but gauze pads and tissue paper placed in the underwear should be avoided

• Patients often find that night times are the worst for the sensation of extreme irritation at the anal margin and a desire to itch the area may become irresistible. An over the counter antihistamine (which may have drowsy making side effects), taken just before bed time, is an ideal way of improving the sensation of itching as well as assisting with sleep. The purchase of cotton gloves from the chemist to wear at night is also useful to prevent further unintentional damage to the perianal skin whilst asleep.

• Occasionally the insertion of a small plug of cotton wool into the anal canal (not on the surrounding skin) may be enough to control mucus or soft stool leakage on to the perianal area for those with uncorrected bowel continence issues. A small piece of cotton wool pushed inside the anal canal will not feel uncomfortable and will always be passed at the time of the next bowel evacuation without problem.

• Loose fitting cotton underwear is ideal and should be changed daily. Tights, tight trousers or jeans and, where possible, prolonged periods of sitting should be avoided. Clothes should be washed in a non biological washing powder.

• Diets low in fibre may make the stools softer and more likely to cause leakage at the anal margin. Using bran and consuming sensible volumes of water as well as modifying intake of fruit and vegetables, particularly those with skins, may improve the consistency of stools to one that is well formed and easily passed. This will decrease discharge of loose stool or mucus from the anal canal.

• Drinks to avoid include alcoholic drinks with high yeast content, such as real ales, coffee, chocolate and fruit juices. Other foods to avoid if possible include milk products, peanuts and spicy foods.

• Medications if possible to avoid include Steroids, Laxatives, Colpermin and Antibiotics.

• Other Conditions that may cause pruritus ani. These should be treated by a doctor.

• Candida infection is very uncommon but easily treated with antifungal ointments.

• Threadworms can infect multiple family members and are easily treated.

• Sexually acquired bacterial and viral infections.

• Allergic contact dermatitis often occurs as a result of the use of multiple topical creams available over the counter at Chemists.

• Psoriasis

• Lichen Planus

Identification of the causes listed above and correction where possible should improve the symptoms of the majority of patients. Meticulous attention to the skin of the perianal area to avoid further injury will result in complete healing in the majority of cases.

The amount of time for which symptoms have been present is a useful indication of the speed with which resolution will occur. This is usually measured in weeks and months rather than days