Pruritus ani is the medical term for any itch in or around the anal area (from the Latin words pruritus, meaning “itch” and ani, meaning “of the anus”). It can be minor and go away of its own accord or be so severe and long-lasting that it can have a severe impact on the life of its sufferers.
Pruritus ani can occur at any age, but seems to be more common in people aged 40–60 years. It occurs more often in men, with some research suggesting that men are up to four times more likely than women to develop the condition. There is no obvious reason why this should be the case, and more research is needed to look into this.
Pruritus ani can be classified as secondary or primary. If a condition is found in the lower bowel, anus, or on the skin surrounding the anus that is suspected to lead to anal itching, pruritus ani is classified as secondary to that condition. If no abnormality can be found in these areas, then the pruritus ani is considered to be primary (or idiopathic, meaning “no known cause”). Traditionally, pruritus ani has been thought of as a symptom rather than as a condition in itself. However, there is recent research suggesting pruritus ani that is initially secondary to another condition causes changes in the nervous system that lead to the itch becoming permanent, even though the original cause of the itch has disappeared.
Most studies suggest an underlying cause in half to three quarters of people with pruritus ani. Some surgeons believe that nearly all cases are secondary to another disorder and that the closer they look, the more likely an underlying cause will be found. Looking at the medical literature published over the past century, approximately 100 conditions have been reported to be associated with pruritus ani.
Any skin condition that causes itching, such as eczema or psoriasis, can affect the skin around the anus and cause pruritus ani just as easily as it can cause itching elsewhere on the body. However, the appearance of the affected skin around the anus may not necessarily look like the skin areas affected by the same condition on other parts of the body. Sometimes a skin biopsy is needed to make the diagnosis. People who are prone to atopic dermatitis may be at increased risk of pruritus ani.
In some people, a particular food item may be associated with pruritus ani, possibly because it makes their stools looser. Unfortunately, no specific dietary advice can be given to any individual patient, other than to see what happens when they avoid particular foods.
Any medical condition affecting the lower bowel, anus, and the surrounding skin can cause itchiness in the anal area. These range from serious conditions such as cancer of the bowel through to haemorrhoids, anal fissures, a weak anal sphincter, and internal rectal prolapse. All of these conditions are made worse if the person’s bowel motions are looser. With all these conditions, faeces may leak from the anus onto the skin outside, causing irritation. This leak may be so small that it goes unnoticed by the patient when cleaning the area or when it is on their underwear. However, the leak does occur and perpetuates the itch. Luckily, there is every chance that pruritus ani will improve if the patient sees a specialist who checks carefully for a secondary cause.
When no definite cause of pruritus ani can be found in a patient who has been fully investigated by colonoscopy, examination under anaesthesia of the anorectum, and biopsy of the skin, the condition is labelled as idiopathic. However, a good surgeon will always have a high level of suspicion that an underlying cause has been missed.
In a small minority of people, bad hygiene can undoubtedly lead to pruritus ani. However, as a general rule, people with pruritus ani are rigorous with their personal hygiene, which can actually make their anal itching worse.
Many people have itchiness around the anal region that resolves spontaneously or with simple measures. Unfortunately, many people who are profoundly troubled by pruritus ani consult health care professionals who do not take them seriously, so their symptoms do not improve. However, on seeking the advice of a specialist who is interested in this condition, most people report a significant improvement in their symptoms and quality of life.
The first step is to stop using any chemicals, including creams, soaps, bubble baths, and toilet paper, around the anal area and only use water for cleansing. Hypoallergenic laundry products are also recommended. Certain foods and drinks are believed to be associated with pruritus ani, and it is well worth eliminating these from the diet for a while to see if this helps. Possible culprits include coffee, tea, cola, energy drinks, chocolate, citrus fruit, tomatoes, spicy foods, beer, dairy products and nuts.
General control measures
The anal area should be cleansed with water alone in the squatting position, making sure to remove any faeces. The area should be patted dry with a soft flannel and dried using a hair dryer if necessary. Water-based creams and emollients can be used if more rigorous cleansing is required. Petroleum ointment, Sudocrem® or Cavilon® should be used as a barrier after cleansing. The anal itch can be hard to deal with when outside the home. Many patients carry a small tube of aqueous cream, which can be used with cotton wool balls to cleanse and coat the anal area after going to the toilet. Patients who sweat excessively can place cotton tissue (unscented products are best) around the anal area. The sedating effect of some antihistamine products may be useful in aiding sleep, but has no effect on the itch itself. Some self-help groups suggest wearing gloves at night to prevent scratching, although this is not always practical.
Mild to moderate symptoms of pruritus ani without skin changes can respond well to hydrocortisone 1% ointment. How often the ointment is applied can be reduced as symptoms improve. This can be used at the same time as barrier creams. Severe symptoms and skin changes can be treated with stronger steroids for up to 8 weeks, and should be replaced with a weaker steroid ointment when symptoms have improved. Occasionally, creams to eradicate fungal infections such as thrush are useful. Antibiotic creams are no longer used.
I am one of the very few specialists in the UK able to perform anal tattooing for pruritus ani. This procedure is generally reserved for patients who cannot be help by other means and for those who have become steroid-dependent. Anal tattooing is performed under general anaesthesia and uses methylene blue to reduce sensation in the anal area, cutting off the sensation of itch. The tattoo itself lasts only a matter of weeks and the skin looks no different in the long term. The skin may have a reduced sensation for up to a year and the procedure can be repeated if necessary.
For more information on pruritus ani, please visit http://patient.info/health/itchy-bottom-pruritus-ani